diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
index fbfe2cf39a77..eac38bf01e46 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
@@ -629,7 +629,7 @@ public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs)
                 List<CodegenProperty> allOf = composedSchemas.getAllOf();
                 if (allOf != null) {
                     for (CodegenProperty property : allOf) {
-                        property.name = patchPropertyName(model, camelize(property.baseType), composedPropertyNames);
+                        property.name = patchPropertyName(model, property, camelize(property.baseType), composedPropertyNames);
                         patchPropertyVendorExtensions(property);
                     }
                 }
@@ -638,7 +638,7 @@ public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs)
                 if (anyOf != null) {
                     removePropertiesDeclaredInComposedTypes(objs, model, anyOf);
                     for (CodegenProperty property : anyOf) {
-                        property.name = patchPropertyName(model, camelize(property.baseType), composedPropertyNames);
+                        property.name = patchPropertyName(model, property, camelize(property.baseType), composedPropertyNames);
                         property.isNullable = true;
                         patchPropertyVendorExtensions(property);
                         property.vendorExtensions.put("x-base-name", model.name.substring(model.name.lastIndexOf('_') + 1));
@@ -649,7 +649,7 @@ public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs)
                 if (oneOf != null) {
                     removePropertiesDeclaredInComposedTypes(objs, model, oneOf);
                     for (CodegenProperty property : oneOf) {
-                        property.name = patchPropertyName(model, camelize(property.baseType), composedPropertyNames);
+                        property.name = patchPropertyName(model, property, camelize(property.baseType), composedPropertyNames);
                         property.isNullable = true;
                         patchPropertyVendorExtensions(property);
                         property.vendorExtensions.put("x-base-name", model.name.substring(model.name.lastIndexOf('_') + 1));
@@ -716,7 +716,51 @@ private boolean modelIsMutable(CodegenModel model, Set<String> processed) {
     protected void removePropertiesDeclaredInComposedTypes(Map<String, ModelsMap> objs, CodegenModel model, List<CodegenProperty> composedProperties) {
     }
 
-    private String patchPropertyName(CodegenModel model, String value, Set<String> composedPropertyNames) {
+    /**
+     * If the model has duplicate proprety names, just make it unique
+     * This can happen for base names like "id" and "@id"
+     * @param model
+     * @param property
+     * @param value
+     * @return
+     */
+    private String setUniquePropertyName(CodegenModel model, CodegenProperty property, String value) {
+        if (property.name.equalsIgnoreCase(property.baseName)) {
+            return value;
+        }
+
+        Optional<CodegenProperty> alreadyUpdatedProperty = model.allVars.stream()
+                .filter(p -> !p.name.equals(property.name) && p.baseName.equals(property.baseName))
+                .collect(Collectors.toList())
+                .stream()
+                .findFirst();
+
+        if (alreadyUpdatedProperty.isPresent()) {
+            // above iterates allVars, which may have already been corrected
+            return alreadyUpdatedProperty.get().name;
+        }
+
+        final String tmp = value;
+
+        long count = model.allVars.stream()
+                .filter(v -> v.name.equalsIgnoreCase(tmp))
+                .count();
+
+        if (count > 1) {
+            value = value + count;
+            value = setUniquePropertyName(model, property, value);
+        }
+
+        return value;
+    }
+
+    /** 
+     * Fixes nested maps so the generic type is defined
+     * Convertes List<List>> to List<List<T>>
+     */
+    private String patchPropertyName(CodegenModel model, CodegenProperty property, String value, Set<String> composedPropertyNames) {
+        value = setUniquePropertyName(model, property, value);
+
         String name = escapeReservedWord(model, value);
 
         if (name.startsWith(AbstractCSharpCodegen.invalidParameterNamePrefix)) {
@@ -799,7 +843,7 @@ protected void patchProperty(Map<String, CodegenModel> enumRefs, CodegenModel mo
 
         patchPropertyVendorExtensions(property);
 
-        property.name = patchPropertyName(model, property.name, null);
+        property.name = patchPropertyName(model, property, property.name, null);
 
         patchNestedMaps(property);
 
diff --git a/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml b/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
index d4a570cdb157..53a2e45a7817 100644
--- a/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
@@ -1780,6 +1780,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
     EnumClass:
       type: string
       default: '-efg'
diff --git a/samples/client/petstore/csharp/generichost/net4.7/FormModels/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net4.7/FormModels/api/openapi.yaml
index 3afd9359ab7d..816608604456 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/FormModels/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net4.7/FormModels/api/openapi.yaml
@@ -1673,6 +1673,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net4.7/FormModels/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net4.7/FormModels/docs/models/FormatTest.md
index 950546c1812f..8ba789fb729e 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/FormModels/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net4.7/FormModels/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
index 1887346c88b6..ae0854b6be45 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net4.7/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new Option<double?>(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new Option<string>(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new Option<string>(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net4.7/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net4.7/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net4.7/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net4.7/Petstore/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net4.7/Petstore/docs/models/FormatTest.md
index 950546c1812f..8ba789fb729e 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/Petstore/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net4.7/Petstore/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 1887346c88b6..ae0854b6be45 100644
--- a/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net4.7/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new Option<double?>(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new Option<string>(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new Option<string>(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net4.8/FormModels/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net4.8/FormModels/api/openapi.yaml
index 3afd9359ab7d..816608604456 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/FormModels/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net4.8/FormModels/api/openapi.yaml
@@ -1673,6 +1673,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net4.8/FormModels/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net4.8/FormModels/docs/models/FormatTest.md
index 950546c1812f..8ba789fb729e 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/FormModels/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net4.8/FormModels/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
index 1887346c88b6..ae0854b6be45 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net4.8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new Option<double?>(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new Option<string>(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new Option<string>(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net4.8/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net4.8/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net4.8/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net4.8/Petstore/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net4.8/Petstore/docs/models/FormatTest.md
index 950546c1812f..8ba789fb729e 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/Petstore/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net4.8/Petstore/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 1887346c88b6..ae0854b6be45 100644
--- a/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net4.8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new Option<double?>(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new Option<string>(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new Option<string>(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net8/FormModels/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net8/FormModels/api/openapi.yaml
index 3afd9359ab7d..816608604456 100644
--- a/samples/client/petstore/csharp/generichost/net8/FormModels/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net8/FormModels/api/openapi.yaml
@@ -1673,6 +1673,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net8/FormModels/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net8/FormModels/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net8/FormModels/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net8/FormModels/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
index 217cf10f2dda..847567dd4b69 100644
--- a/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net8/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs
index a5dae71ad9d4..9e4b3c23fe8a 100644
--- a/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net8/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -43,6 +43,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -61,7 +63,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string?> duplicatePropertyName2 = default, Option<string?> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -72,6 +74,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -178,6 +182,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string? DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string? DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -426,6 +456,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -660,6 +692,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string?> duplicatePropertyName2 = default;
+            Option<string?> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -720,6 +754,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -819,6 +859,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -870,7 +916,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -906,6 +952,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -944,6 +996,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value!.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value!.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net8/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net8/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net8/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net8/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net8/Petstore/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net8/Petstore/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net8/Petstore/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net8/Petstore/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 217cf10f2dda..847567dd4b69 100644
--- a/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs
index 894fa9a3fa82..3daacf80952d 100644
--- a/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net8/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -44,6 +44,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -62,7 +64,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string?> duplicatePropertyName2 = default, Option<string?> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -73,6 +75,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -179,6 +183,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string? DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string? DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -427,6 +457,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -661,6 +693,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string?> duplicatePropertyName2 = default;
+            Option<string?> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -721,6 +755,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -820,6 +860,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -871,7 +917,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -907,6 +953,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -945,6 +997,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value!.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value!.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net9/FormModels/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net9/FormModels/api/openapi.yaml
index 3afd9359ab7d..816608604456 100644
--- a/samples/client/petstore/csharp/generichost/net9/FormModels/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net9/FormModels/api/openapi.yaml
@@ -1673,6 +1673,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net9/FormModels/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net9/FormModels/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net9/FormModels/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net9/FormModels/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
index 217cf10f2dda..847567dd4b69 100644
--- a/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net9/FormModels/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs
index a5dae71ad9d4..9e4b3c23fe8a 100644
--- a/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net9/NullReferenceTypes/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -43,6 +43,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -61,7 +63,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string?> duplicatePropertyName2 = default, Option<string?> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -72,6 +74,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -178,6 +182,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string? DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string? DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -426,6 +456,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -660,6 +692,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string?> duplicatePropertyName2 = default;
+            Option<string?> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -720,6 +754,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -819,6 +859,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -870,7 +916,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -906,6 +952,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -944,6 +996,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value!.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value!.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net9/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net9/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net9/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net9/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net9/Petstore/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net9/Petstore/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net9/Petstore/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net9/Petstore/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 217cf10f2dda..847567dd4b69 100644
--- a/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/api/openapi.yaml b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/docs/models/FormatTest.md
index 8380bbcb5564..8ef56b994400 100644
--- a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs
index 894fa9a3fa82..3daacf80952d 100644
--- a/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/net9/SourceGeneration/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -44,6 +44,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -62,7 +64,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateOnly date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream?> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string?> duplicatePropertyName2 = default, Option<string?> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string?> patternWithBackslash = default, Option<string?> patternWithDigits = default, Option<string?> patternWithDigitsAndDelimiter = default, Option<string?> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -73,6 +75,8 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -179,6 +183,32 @@ public FormatTest(byte[] @byte, DateOnly date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string? DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string?> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string? DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -427,6 +457,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -661,6 +693,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string?> duplicatePropertyName2 = default;
+            Option<string?> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -721,6 +755,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string?>(utf8JsonReader.GetString()!);
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -820,6 +860,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -871,7 +917,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value!, date.Value!.Value!, number.Value!.Value!, password.Value!, stringFormattedAsDecimalRequired.Value!.Value!, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -907,6 +953,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -945,6 +997,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value!.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value!.Value);
 
diff --git a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/docs/models/FormatTest.md b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/docs/models/FormatTest.md
index 950546c1812f..8ba789fb729e 100644
--- a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/docs/models/FormatTest.md
+++ b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/docs/models/FormatTest.md
@@ -13,6 +13,8 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Decimal** | **decimal** |  | [optional] 
 **Double** | **double** |  | [optional] 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 **Float** | **float** |  | [optional] 
 **Int32** | **int** |  | [optional] 
 **Int32Range** | **int** |  | [optional] 
diff --git a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
index fe89f7090c4c..a144a3103489 100644
--- a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
+++ b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools.Test/Model/FormatTestTests.cs
@@ -134,6 +134,24 @@ public void DoubleTest()
             // TODO unit test for the property 'Double'
         }
 
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName2'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyName2Test()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName2'
+        }
+
+        /// <summary>
+        /// Test the property 'DuplicatePropertyName'
+        /// </summary>
+        [Fact]
+        public void DuplicatePropertyNameTest()
+        {
+            // TODO unit test for the property 'DuplicatePropertyName'
+        }
+
         /// <summary>
         /// Test the property 'Float'
         /// </summary>
diff --git a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 1887346c88b6..ae0854b6be45 100644
--- a/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/generichost/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -41,6 +41,8 @@ public partial class FormatTest : IValidatableObject
         /// <param name="dateTime">dateTime</param>
         /// <param name="decimal">decimal</param>
         /// <param name="double">double</param>
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName</param>
         /// <param name="float">float</param>
         /// <param name="int32">int32</param>
         /// <param name="int32Range">int32Range</param>
@@ -59,7 +61,7 @@ public partial class FormatTest : IValidatableObject
         /// <param name="unsignedLong">unsignedLong</param>
         /// <param name="uuid">uuid</param>
         [JsonConstructor]
-        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
+        public FormatTest(byte[] @byte, DateTime date, decimal number, string password, decimal stringFormattedAsDecimalRequired, Option<System.IO.Stream> binary = default, Option<DateTime?> dateTime = default, Option<decimal?> @decimal = default, Option<double?> @double = default, Option<string> duplicatePropertyName2 = default, Option<string> duplicatePropertyName = default, Option<float?> @float = default, Option<int?> int32 = default, Option<int?> int32Range = default, Option<long?> int64 = default, Option<long?> int64Negative = default, Option<long?> int64NegativeExclusive = default, Option<long?> int64Positive = default, Option<long?> int64PositiveExclusive = default, Option<int?> integer = default, Option<string> patternWithBackslash = default, Option<string> patternWithDigits = default, Option<string> patternWithDigitsAndDelimiter = default, Option<string> @string = default, Option<decimal?> stringFormattedAsDecimal = default, Option<uint?> unsignedInteger = default, Option<ulong?> unsignedLong = default, Option<Guid?> uuid = default)
         {
             Byte = @byte;
             Date = date;
@@ -70,6 +72,8 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
             DateTimeOption = dateTime;
             DecimalOption = @decimal;
             DoubleOption = @double;
+            DuplicatePropertyName2Option = duplicatePropertyName2;
+            DuplicatePropertyNameOption = duplicatePropertyName;
             FloatOption = @float;
             Int32Option = int32;
             Int32RangeOption = int32Range;
@@ -176,6 +180,32 @@ public FormatTest(byte[] @byte, DateTime date, decimal number, string password,
         [JsonPropertyName("double")]
         public double? Double { get { return this.DoubleOption; } set { this.DoubleOption = new Option<double?>(value); } }
 
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName2
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyName2Option { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [JsonPropertyName("duplicate_property_name")]
+        public string DuplicatePropertyName2 { get { return this.DuplicatePropertyName2Option; } set { this.DuplicatePropertyName2Option = new Option<string>(value); } }
+
+        /// <summary>
+        /// Used to track the state of DuplicatePropertyName
+        /// </summary>
+        [JsonIgnore]
+        [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public Option<string> DuplicatePropertyNameOption { get; private set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [JsonPropertyName("@duplicate_property_name")]
+        public string DuplicatePropertyName { get { return this.DuplicatePropertyNameOption; } set { this.DuplicatePropertyNameOption = new Option<string>(value); } }
+
         /// <summary>
         /// Used to track the state of Float
         /// </summary>
@@ -424,6 +454,8 @@ public override string ToString()
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Decimal: ").Append(Decimal).Append("\n");
             sb.Append("  Double: ").Append(Double).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  Float: ").Append(Float).Append("\n");
             sb.Append("  Int32: ").Append(Int32).Append("\n");
             sb.Append("  Int32Range: ").Append(Int32Range).Append("\n");
@@ -658,6 +690,8 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             Option<DateTime?> dateTime = default;
             Option<decimal?> varDecimal = default;
             Option<double?> varDouble = default;
+            Option<string> duplicatePropertyName2 = default;
+            Option<string> duplicatePropertyName = default;
             Option<float?> varFloat = default;
             Option<int?> int32 = default;
             Option<int?> int32Range = default;
@@ -718,6 +752,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
                         case "double":
                             varDouble = new Option<double?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (double?)null : utf8JsonReader.GetDouble());
                             break;
+                        case "duplicate_property_name":
+                            duplicatePropertyName2 = new Option<string>(utf8JsonReader.GetString());
+                            break;
+                        case "@duplicate_property_name":
+                            duplicatePropertyName = new Option<string>(utf8JsonReader.GetString());
+                            break;
                         case "float":
                             varFloat = new Option<float?>(utf8JsonReader.TokenType == JsonTokenType.Null ? (float?)null : (float)utf8JsonReader.GetDouble());
                             break;
@@ -817,6 +857,12 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (varDouble.IsSet && varDouble.Value == null)
                 throw new ArgumentNullException(nameof(varDouble), "Property is not nullable for class FormatTest.");
 
+            if (duplicatePropertyName2.IsSet && duplicatePropertyName2.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName2), "Property is not nullable for class FormatTest.");
+
+            if (duplicatePropertyName.IsSet && duplicatePropertyName.Value == null)
+                throw new ArgumentNullException(nameof(duplicatePropertyName), "Property is not nullable for class FormatTest.");
+
             if (varFloat.IsSet && varFloat.Value == null)
                 throw new ArgumentNullException(nameof(varFloat), "Property is not nullable for class FormatTest.");
 
@@ -868,7 +914,7 @@ public override FormatTest Read(ref Utf8JsonReader utf8JsonReader, Type typeToCo
             if (uuid.IsSet && uuid.Value == null)
                 throw new ArgumentNullException(nameof(uuid), "Property is not nullable for class FormatTest.");
 
-            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
+            return new FormatTest(varByte.Value, date.Value.Value, number.Value.Value, password.Value, stringFormattedAsDecimalRequired.Value.Value, binary, dateTime, varDecimal, varDouble, duplicatePropertyName2, duplicatePropertyName, varFloat, int32, int32Range, int64, int64Negative, int64NegativeExclusive, int64Positive, int64PositiveExclusive, integer, patternWithBackslash, patternWithDigits, patternWithDigitsAndDelimiter, varString, stringFormattedAsDecimal, unsignedInteger, unsignedLong, uuid);
         }
 
         /// <summary>
@@ -904,6 +950,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.BinaryOption.IsSet && formatTest.Binary == null)
                 throw new ArgumentNullException(nameof(formatTest.Binary), "Property is required for class FormatTest.");
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet && formatTest.DuplicatePropertyName2 == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName2), "Property is required for class FormatTest.");
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet && formatTest.DuplicatePropertyName == null)
+                throw new ArgumentNullException(nameof(formatTest.DuplicatePropertyName), "Property is required for class FormatTest.");
+
             if (formatTest.PatternWithBackslashOption.IsSet && formatTest.PatternWithBackslash == null)
                 throw new ArgumentNullException(nameof(formatTest.PatternWithBackslash), "Property is required for class FormatTest.");
 
@@ -942,6 +994,12 @@ public void WriteProperties(Utf8JsonWriter writer, FormatTest formatTest, JsonSe
             if (formatTest.DoubleOption.IsSet)
                 writer.WriteNumber("double", formatTest.DoubleOption.Value.Value);
 
+            if (formatTest.DuplicatePropertyName2Option.IsSet)
+                writer.WriteString("duplicate_property_name", formatTest.DuplicatePropertyName2);
+
+            if (formatTest.DuplicatePropertyNameOption.IsSet)
+                writer.WriteString("@duplicate_property_name", formatTest.DuplicatePropertyName);
+
             if (formatTest.FloatOption.IsSet)
                 writer.WriteNumber("float", formatTest.FloatOption.Value.Value);
 
diff --git a/samples/client/petstore/csharp/httpclient/net9/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/httpclient/net9/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/httpclient/net9/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/httpclient/net9/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/httpclient/net9/Petstore/docs/FormatTest.md b/samples/client/petstore/csharp/httpclient/net9/Petstore/docs/FormatTest.md
index 25a96509f1d5..3d9c0c9d5d30 100644
--- a/samples/client/petstore/csharp/httpclient/net9/Petstore/docs/FormatTest.md
+++ b/samples/client/petstore/csharp/httpclient/net9/Petstore/docs/FormatTest.md
@@ -30,6 +30,8 @@ Name | Type | Description | Notes
 **PatternWithBackslash** | **string** | None | [optional] 
 **StringFormattedAsDecimal** | **decimal** |  | [optional] 
 **StringFormattedAsDecimalRequired** | **decimal** |  | 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp/httpclient/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/httpclient/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 70e020f818c6..31cc93ec432b 100644
--- a/samples/client/petstore/csharp/httpclient/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/httpclient/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -70,7 +70,9 @@ protected FormatTest()
         /// <param name="patternWithBackslash">None.</param>
         /// <param name="stringFormattedAsDecimal">stringFormattedAsDecimal.</param>
         /// <param name="stringFormattedAsDecimalRequired">stringFormattedAsDecimalRequired (required).</param>
-        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, FileParameter binary = default, DateOnly date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default)
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2.</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName.</param>
+        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, FileParameter binary = default, DateOnly date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default, string duplicatePropertyName2 = default, string duplicatePropertyName = default)
         {
             this.Number = number;
             // to ensure "varByte" is required (not null)
@@ -108,6 +110,8 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
             this.PatternWithDigitsAndDelimiter = patternWithDigitsAndDelimiter;
             this.PatternWithBackslash = patternWithBackslash;
             this.StringFormattedAsDecimal = stringFormattedAsDecimal;
+            this.DuplicatePropertyName2 = duplicatePropertyName2;
+            this.DuplicatePropertyName = duplicatePropertyName;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
@@ -279,6 +283,18 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
         [DataMember(Name = "string_formatted_as_decimal_required", IsRequired = true, EmitDefaultValue = true)]
         public decimal StringFormattedAsDecimalRequired { get; set; }
 
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [DataMember(Name = "duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName2 { get; set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [DataMember(Name = "@duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName { get; set; }
+
         /// <summary>
         /// Gets or Sets additional properties
         /// </summary>
@@ -319,6 +335,8 @@ public override string ToString()
             sb.Append("  PatternWithBackslash: ").Append(PatternWithBackslash).Append("\n");
             sb.Append("  StringFormattedAsDecimal: ").Append(StringFormattedAsDecimal).Append("\n");
             sb.Append("  StringFormattedAsDecimalRequired: ").Append(StringFormattedAsDecimalRequired).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  AdditionalProperties: ").Append(AdditionalProperties).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
@@ -418,6 +436,14 @@ public override int GetHashCode()
                 }
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimal.GetHashCode();
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimalRequired.GetHashCode();
+                if (this.DuplicatePropertyName2 != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName2.GetHashCode();
+                }
+                if (this.DuplicatePropertyName != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName.GetHashCode();
+                }
                 if (this.AdditionalProperties != null)
                 {
                     hashCode = (hashCode * 59) + this.AdditionalProperties.GetHashCode();
diff --git a/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/docs/FormatTest.md b/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/docs/FormatTest.md
index e6ba5f68b3fe..d8093d01992c 100644
--- a/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/docs/FormatTest.md
+++ b/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/docs/FormatTest.md
@@ -30,6 +30,8 @@ Name | Type | Description | Notes
 **PatternWithBackslash** | **string** | None | [optional] 
 **StringFormattedAsDecimal** | **decimal** |  | [optional] 
 **StringFormattedAsDecimalRequired** | **decimal** |  | 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 0730a2282086..01d0c792593b 100644
--- a/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/httpclient/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -70,7 +70,9 @@ protected FormatTest()
         /// <param name="patternWithBackslash">None.</param>
         /// <param name="stringFormattedAsDecimal">stringFormattedAsDecimal.</param>
         /// <param name="stringFormattedAsDecimalRequired">stringFormattedAsDecimalRequired (required).</param>
-        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, FileParameter binary = default, DateTime date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default)
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2.</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName.</param>
+        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, FileParameter binary = default, DateTime date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default, string duplicatePropertyName2 = default, string duplicatePropertyName = default)
         {
             this.Number = number;
             // to ensure "varByte" is required (not null)
@@ -108,6 +110,8 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
             this.PatternWithDigitsAndDelimiter = patternWithDigitsAndDelimiter;
             this.PatternWithBackslash = patternWithBackslash;
             this.StringFormattedAsDecimal = stringFormattedAsDecimal;
+            this.DuplicatePropertyName2 = duplicatePropertyName2;
+            this.DuplicatePropertyName = duplicatePropertyName;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
@@ -280,6 +284,18 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
         [DataMember(Name = "string_formatted_as_decimal_required", IsRequired = true, EmitDefaultValue = true)]
         public decimal StringFormattedAsDecimalRequired { get; set; }
 
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [DataMember(Name = "duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName2 { get; set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [DataMember(Name = "@duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName { get; set; }
+
         /// <summary>
         /// Gets or Sets additional properties
         /// </summary>
@@ -320,6 +336,8 @@ public override string ToString()
             sb.Append("  PatternWithBackslash: ").Append(PatternWithBackslash).Append("\n");
             sb.Append("  StringFormattedAsDecimal: ").Append(StringFormattedAsDecimal).Append("\n");
             sb.Append("  StringFormattedAsDecimalRequired: ").Append(StringFormattedAsDecimalRequired).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  AdditionalProperties: ").Append(AdditionalProperties).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
@@ -419,6 +437,14 @@ public override int GetHashCode()
                 }
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimal.GetHashCode();
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimalRequired.GetHashCode();
+                if (this.DuplicatePropertyName2 != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName2.GetHashCode();
+                }
+                if (this.DuplicatePropertyName != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName.GetHashCode();
+                }
                 if (this.AdditionalProperties != null)
                 {
                     hashCode = (hashCode * 59) + this.AdditionalProperties.GetHashCode();
diff --git a/samples/client/petstore/csharp/restsharp/net8/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/restsharp/net8/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/restsharp/net8/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/restsharp/net8/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/restsharp/net8/Petstore/docs/FormatTest.md b/samples/client/petstore/csharp/restsharp/net8/Petstore/docs/FormatTest.md
index 5c185c58a738..4a6a9bee84d5 100644
--- a/samples/client/petstore/csharp/restsharp/net8/Petstore/docs/FormatTest.md
+++ b/samples/client/petstore/csharp/restsharp/net8/Petstore/docs/FormatTest.md
@@ -30,6 +30,8 @@ Name | Type | Description | Notes
 **PatternWithBackslash** | **string** | None | [optional] 
 **StringFormattedAsDecimal** | **decimal** |  | [optional] 
 **StringFormattedAsDecimalRequired** | **decimal** |  | 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp/restsharp/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/restsharp/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 408766a19d16..7f8d2409a609 100644
--- a/samples/client/petstore/csharp/restsharp/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/restsharp/net8/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -66,7 +66,9 @@ protected FormatTest() { }
         /// <param name="patternWithBackslash">None.</param>
         /// <param name="stringFormattedAsDecimal">stringFormattedAsDecimal.</param>
         /// <param name="stringFormattedAsDecimalRequired">stringFormattedAsDecimalRequired (required).</param>
-        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateOnly date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default)
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2.</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName.</param>
+        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateOnly date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default, string duplicatePropertyName2 = default, string duplicatePropertyName = default)
         {
             this.Number = number;
             // to ensure "varByte" is required (not null)
@@ -104,6 +106,8 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
             this.PatternWithDigitsAndDelimiter = patternWithDigitsAndDelimiter;
             this.PatternWithBackslash = patternWithBackslash;
             this.StringFormattedAsDecimal = stringFormattedAsDecimal;
+            this.DuplicatePropertyName2 = duplicatePropertyName2;
+            this.DuplicatePropertyName = duplicatePropertyName;
         }
 
         /// <summary>
@@ -274,6 +278,18 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
         [DataMember(Name = "string_formatted_as_decimal_required", IsRequired = true, EmitDefaultValue = true)]
         public decimal StringFormattedAsDecimalRequired { get; set; }
 
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [DataMember(Name = "duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName2 { get; set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [DataMember(Name = "@duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName { get; set; }
+
         /// <summary>
         /// Returns the string presentation of the object
         /// </summary>
@@ -308,6 +324,8 @@ public override string ToString()
             sb.Append("  PatternWithBackslash: ").Append(PatternWithBackslash).Append("\n");
             sb.Append("  StringFormattedAsDecimal: ").Append(StringFormattedAsDecimal).Append("\n");
             sb.Append("  StringFormattedAsDecimalRequired: ").Append(StringFormattedAsDecimalRequired).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
         }
@@ -406,6 +424,14 @@ public override int GetHashCode()
                 }
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimal.GetHashCode();
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimalRequired.GetHashCode();
+                if (this.DuplicatePropertyName2 != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName2.GetHashCode();
+                }
+                if (this.DuplicatePropertyName != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName.GetHashCode();
+                }
                 return hashCode;
             }
         }
diff --git a/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/api/openapi.yaml b/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/api/openapi.yaml
+++ b/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/docs/FormatTest.md b/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/docs/FormatTest.md
index 2c414708d688..c6080dc129b5 100644
--- a/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/docs/FormatTest.md
+++ b/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/docs/FormatTest.md
@@ -30,6 +30,8 @@ Name | Type | Description | Notes
 **PatternWithBackslash** | **string** | None | [optional] 
 **StringFormattedAsDecimal** | **decimal** |  | [optional] 
 **StringFormattedAsDecimalRequired** | **decimal** |  | 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/src/Org.OpenAPITools/Model/FormatTest.cs
index c1d79614e1ef..cb78ccd5bd53 100644
--- a/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/restsharp/standard2.0/ConditionalSerialization/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -69,7 +69,9 @@ protected FormatTest()
         /// <param name="patternWithBackslash">None.</param>
         /// <param name="stringFormattedAsDecimal">stringFormattedAsDecimal.</param>
         /// <param name="stringFormattedAsDecimalRequired">stringFormattedAsDecimalRequired (required).</param>
-        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateTime date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default)
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2.</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName.</param>
+        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateTime date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default, string duplicatePropertyName2 = default, string duplicatePropertyName = default)
         {
             this._Number = number;
             // to ensure "varByte" is required (not null)
@@ -191,6 +193,16 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
             {
                 this._flagStringFormattedAsDecimal = true;
             }
+            this._DuplicatePropertyName2 = duplicatePropertyName2;
+            if (this.DuplicatePropertyName2 != null)
+            {
+                this._flagDuplicatePropertyName2 = true;
+            }
+            this._DuplicatePropertyName = duplicatePropertyName;
+            if (this.DuplicatePropertyName != null)
+            {
+                this._flagDuplicatePropertyName = true;
+            }
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
@@ -832,6 +844,54 @@ public bool ShouldSerializeStringFormattedAsDecimalRequired()
             return _flagStringFormattedAsDecimalRequired;
         }
         /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [DataMember(Name = "duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName2
+        {
+            get{ return _DuplicatePropertyName2;}
+            set
+            {
+                _DuplicatePropertyName2 = value;
+                _flagDuplicatePropertyName2 = true;
+            }
+        }
+        private string _DuplicatePropertyName2;
+        private bool _flagDuplicatePropertyName2;
+
+        /// <summary>
+        /// Returns false as DuplicatePropertyName2 should not be serialized given that it's read-only.
+        /// </summary>
+        /// <returns>false (boolean)</returns>
+        public bool ShouldSerializeDuplicatePropertyName2()
+        {
+            return _flagDuplicatePropertyName2;
+        }
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [DataMember(Name = "@duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName
+        {
+            get{ return _DuplicatePropertyName;}
+            set
+            {
+                _DuplicatePropertyName = value;
+                _flagDuplicatePropertyName = true;
+            }
+        }
+        private string _DuplicatePropertyName;
+        private bool _flagDuplicatePropertyName;
+
+        /// <summary>
+        /// Returns false as DuplicatePropertyName should not be serialized given that it's read-only.
+        /// </summary>
+        /// <returns>false (boolean)</returns>
+        public bool ShouldSerializeDuplicatePropertyName()
+        {
+            return _flagDuplicatePropertyName;
+        }
+        /// <summary>
         /// Gets or Sets additional properties
         /// </summary>
         [JsonExtensionData]
@@ -871,6 +931,8 @@ public override string ToString()
             sb.Append("  PatternWithBackslash: ").Append(PatternWithBackslash).Append("\n");
             sb.Append("  StringFormattedAsDecimal: ").Append(StringFormattedAsDecimal).Append("\n");
             sb.Append("  StringFormattedAsDecimalRequired: ").Append(StringFormattedAsDecimalRequired).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("  AdditionalProperties: ").Append(AdditionalProperties).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
@@ -970,6 +1032,14 @@ public override int GetHashCode()
                 }
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimal.GetHashCode();
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimalRequired.GetHashCode();
+                if (this.DuplicatePropertyName2 != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName2.GetHashCode();
+                }
+                if (this.DuplicatePropertyName != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName.GetHashCode();
+                }
                 if (this.AdditionalProperties != null)
                 {
                     hashCode = (hashCode * 59) + this.AdditionalProperties.GetHashCode();
diff --git a/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/docs/FormatTest.md b/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/docs/FormatTest.md
index 5c185c58a738..4a6a9bee84d5 100644
--- a/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/docs/FormatTest.md
+++ b/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/docs/FormatTest.md
@@ -30,6 +30,8 @@ Name | Type | Description | Notes
 **PatternWithBackslash** | **string** | None | [optional] 
 **StringFormattedAsDecimal** | **decimal** |  | [optional] 
 **StringFormattedAsDecimalRequired** | **decimal** |  | 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 1affba019b01..def0153c3f5b 100644
--- a/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/unityWebRequest/net9/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -64,7 +64,9 @@ protected FormatTest() { }
         /// <param name="patternWithBackslash">None.</param>
         /// <param name="stringFormattedAsDecimal">stringFormattedAsDecimal.</param>
         /// <param name="stringFormattedAsDecimalRequired">stringFormattedAsDecimalRequired (required).</param>
-        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateOnly date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default)
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2.</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName.</param>
+        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateOnly date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default, string duplicatePropertyName2 = default, string duplicatePropertyName = default)
         {
             this.Number = number;
             // to ensure "varByte" is required (not null)
@@ -102,6 +104,8 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
             this.PatternWithDigitsAndDelimiter = patternWithDigitsAndDelimiter;
             this.PatternWithBackslash = patternWithBackslash;
             this.StringFormattedAsDecimal = stringFormattedAsDecimal;
+            this.DuplicatePropertyName2 = duplicatePropertyName2;
+            this.DuplicatePropertyName = duplicatePropertyName;
         }
 
         /// <summary>
@@ -272,6 +276,18 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
         [DataMember(Name = "string_formatted_as_decimal_required", IsRequired = true, EmitDefaultValue = true)]
         public decimal StringFormattedAsDecimalRequired { get; set; }
 
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [DataMember(Name = "duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName2 { get; set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [DataMember(Name = "@duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName { get; set; }
+
         /// <summary>
         /// Returns the string presentation of the object
         /// </summary>
@@ -306,6 +322,8 @@ public override string ToString()
             sb.Append("  PatternWithBackslash: ").Append(PatternWithBackslash).Append("\n");
             sb.Append("  StringFormattedAsDecimal: ").Append(StringFormattedAsDecimal).Append("\n");
             sb.Append("  StringFormattedAsDecimalRequired: ").Append(StringFormattedAsDecimalRequired).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
         }
@@ -454,6 +472,16 @@ public bool Equals(FormatTest input)
                 (
                     this.StringFormattedAsDecimalRequired == input.StringFormattedAsDecimalRequired ||
                     this.StringFormattedAsDecimalRequired.Equals(input.StringFormattedAsDecimalRequired)
+                ) && 
+                (
+                    this.DuplicatePropertyName2 == input.DuplicatePropertyName2 ||
+                    (this.DuplicatePropertyName2 != null &&
+                    this.DuplicatePropertyName2.Equals(input.DuplicatePropertyName2))
+                ) && 
+                (
+                    this.DuplicatePropertyName == input.DuplicatePropertyName ||
+                    (this.DuplicatePropertyName != null &&
+                    this.DuplicatePropertyName.Equals(input.DuplicatePropertyName))
                 );
         }
 
@@ -522,6 +550,14 @@ public override int GetHashCode()
                 }
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimal.GetHashCode();
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimalRequired.GetHashCode();
+                if (this.DuplicatePropertyName2 != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName2.GetHashCode();
+                }
+                if (this.DuplicatePropertyName != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName.GetHashCode();
+                }
                 return hashCode;
             }
         }
diff --git a/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/api/openapi.yaml b/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/api/openapi.yaml
index d86a1d2f6d87..1aa598117f1a 100644
--- a/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/api/openapi.yaml
+++ b/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/api/openapi.yaml
@@ -1714,6 +1714,10 @@ components:
         string_formatted_as_decimal_required:
           format: decimal
           type: string
+        duplicate_property_name:
+          type: string
+        '@duplicate_property_name':
+          type: string
       required:
       - byte
       - date
diff --git a/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/docs/FormatTest.md b/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/docs/FormatTest.md
index 2c414708d688..c6080dc129b5 100644
--- a/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/docs/FormatTest.md
+++ b/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/docs/FormatTest.md
@@ -30,6 +30,8 @@ Name | Type | Description | Notes
 **PatternWithBackslash** | **string** | None | [optional] 
 **StringFormattedAsDecimal** | **decimal** |  | [optional] 
 **StringFormattedAsDecimalRequired** | **decimal** |  | 
+**DuplicatePropertyName2** | **string** |  | [optional] 
+**DuplicatePropertyName** | **string** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs b/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
index 72cc4eb653f5..087552f5aa82 100644
--- a/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/unityWebRequest/standard2.0/Petstore/src/Org.OpenAPITools/Model/FormatTest.cs
@@ -64,7 +64,9 @@ protected FormatTest() { }
         /// <param name="patternWithBackslash">None.</param>
         /// <param name="stringFormattedAsDecimal">stringFormattedAsDecimal.</param>
         /// <param name="stringFormattedAsDecimalRequired">stringFormattedAsDecimalRequired (required).</param>
-        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateTime date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default)
+        /// <param name="duplicatePropertyName2">duplicatePropertyName2.</param>
+        /// <param name="duplicatePropertyName">duplicatePropertyName.</param>
+        public FormatTest(int integer = default, int int32 = default, int int32Range = default, int int64Positive = default, int int64Negative = default, int int64PositiveExclusive = default, int int64NegativeExclusive = default, uint unsignedInteger = default, long int64 = default, ulong unsignedLong = default, decimal number = default, float varFloat = default, double varDouble = default, decimal varDecimal = default, string varString = default, byte[] varByte = default, System.IO.Stream binary = default, DateTime date = default, DateTime dateTime = default, Guid uuid = default, string password = default, string patternWithDigits = default, string patternWithDigitsAndDelimiter = default, string patternWithBackslash = default, decimal stringFormattedAsDecimal = default, decimal stringFormattedAsDecimalRequired = default, string duplicatePropertyName2 = default, string duplicatePropertyName = default)
         {
             this.Number = number;
             // to ensure "varByte" is required (not null)
@@ -102,6 +104,8 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
             this.PatternWithDigitsAndDelimiter = patternWithDigitsAndDelimiter;
             this.PatternWithBackslash = patternWithBackslash;
             this.StringFormattedAsDecimal = stringFormattedAsDecimal;
+            this.DuplicatePropertyName2 = duplicatePropertyName2;
+            this.DuplicatePropertyName = duplicatePropertyName;
         }
 
         /// <summary>
@@ -273,6 +277,18 @@ public FormatTest(int integer = default, int int32 = default, int int32Range = d
         [DataMember(Name = "string_formatted_as_decimal_required", IsRequired = true, EmitDefaultValue = true)]
         public decimal StringFormattedAsDecimalRequired { get; set; }
 
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName2
+        /// </summary>
+        [DataMember(Name = "duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName2 { get; set; }
+
+        /// <summary>
+        /// Gets or Sets DuplicatePropertyName
+        /// </summary>
+        [DataMember(Name = "@duplicate_property_name", EmitDefaultValue = false)]
+        public string DuplicatePropertyName { get; set; }
+
         /// <summary>
         /// Returns the string presentation of the object
         /// </summary>
@@ -307,6 +323,8 @@ public override string ToString()
             sb.Append("  PatternWithBackslash: ").Append(PatternWithBackslash).Append("\n");
             sb.Append("  StringFormattedAsDecimal: ").Append(StringFormattedAsDecimal).Append("\n");
             sb.Append("  StringFormattedAsDecimalRequired: ").Append(StringFormattedAsDecimalRequired).Append("\n");
+            sb.Append("  DuplicatePropertyName2: ").Append(DuplicatePropertyName2).Append("\n");
+            sb.Append("  DuplicatePropertyName: ").Append(DuplicatePropertyName).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
         }
@@ -455,6 +473,16 @@ public bool Equals(FormatTest input)
                 (
                     this.StringFormattedAsDecimalRequired == input.StringFormattedAsDecimalRequired ||
                     this.StringFormattedAsDecimalRequired.Equals(input.StringFormattedAsDecimalRequired)
+                ) && 
+                (
+                    this.DuplicatePropertyName2 == input.DuplicatePropertyName2 ||
+                    (this.DuplicatePropertyName2 != null &&
+                    this.DuplicatePropertyName2.Equals(input.DuplicatePropertyName2))
+                ) && 
+                (
+                    this.DuplicatePropertyName == input.DuplicatePropertyName ||
+                    (this.DuplicatePropertyName != null &&
+                    this.DuplicatePropertyName.Equals(input.DuplicatePropertyName))
                 );
         }
 
@@ -523,6 +551,14 @@ public override int GetHashCode()
                 }
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimal.GetHashCode();
                 hashCode = (hashCode * 59) + this.StringFormattedAsDecimalRequired.GetHashCode();
+                if (this.DuplicatePropertyName2 != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName2.GetHashCode();
+                }
+                if (this.DuplicatePropertyName != null)
+                {
+                    hashCode = (hashCode * 59) + this.DuplicatePropertyName.GetHashCode();
+                }
                 return hashCode;
             }
         }