diff --git a/src/HotChocolate/Core/src/Execution.Projections/SelectionExpressionBuilder.cs b/src/HotChocolate/Core/src/Execution.Projections/SelectionExpressionBuilder.cs
index 589e0f1b9ac..78a6d6838cb 100644
--- a/src/HotChocolate/Core/src/Execution.Projections/SelectionExpressionBuilder.cs
+++ b/src/HotChocolate/Core/src/Execution.Projections/SelectionExpressionBuilder.cs
@@ -168,10 +168,11 @@ private void CollectTypes(Context context, Selection selection, TypeContainer pa
                 var typeCondition = Expression.TypeIs(context.Parent, typeNode.Type);
                 var selectionSet = BuildSelectionSetExpression(newContext, typeNode);
 
-                if (selectionSet is null)
-                {
-                    throw new InvalidOperationException();
-                }
+                // If a type condition only selects non-bindable fields like __typename,
+                // BuildSelectionSetExpression returns null. Reuse the source instance
+                // instead so the branch remains query-parameter dependent and does not
+                // get parameterized as a constant by EF.
+                selectionSet ??= newParent;
 
                 var castedSelectionSet = Expression.Convert(selectionSet, context.ParentType);
                 switchExpression = Expression.Condition(typeCondition, castedSelectionSet, switchExpression);
diff --git a/src/HotChocolate/Data/src/Data/Projections/Expressions/QueryableProjectionScopeExtensions.cs b/src/HotChocolate/Data/src/Data/Projections/Expressions/QueryableProjectionScopeExtensions.cs
index 3aa02986869..9f71416f121 100644
--- a/src/HotChocolate/Data/src/Data/Projections/Expressions/QueryableProjectionScopeExtensions.cs
+++ b/src/HotChocolate/Data/src/Data/Projections/Expressions/QueryableProjectionScopeExtensions.cs
@@ -41,14 +41,28 @@ public static Expression CreateMemberInit(this QueryableProjectionScope scope)
         if (scope.HasAbstractTypes())
         {
             Expression lastValue = Expression.Default(scope.RuntimeType);
+            var sourceInstance = scope.Instance.Peek();
 
             foreach (var val in scope.GetAbstractTypes())
             {
-                var ctor = Expression.New(val.Key);
-                Expression memberInit = Expression.MemberInit(ctor, val.Value);
+                Expression memberInit;
+
+                // If a type condition only selects non-bindable fields like __typename,
+                // creating `new TDerived()` is evaluatable and gets parameterized as a
+                // constant by EF. Reuse the source instance instead so the branch
+                // remains query-parameter dependent.
+                if (val.Value.Count == 0)
+                {
+                    memberInit = Expression.Convert(sourceInstance, val.Key);
+                }
+                else
+                {
+                    var ctor = Expression.New(val.Key);
+                    memberInit = Expression.MemberInit(ctor, val.Value);
+                }
 
                 lastValue = Expression.Condition(
-                    Expression.TypeIs(scope.Instance.Peek(), val.Key),
+                    Expression.TypeIs(sourceInstance, val.Key),
                     Expression.Convert(memberInit, scope.RuntimeType),
                     lastValue);
             }
diff --git a/src/HotChocolate/Data/test/Data.EntityFramework.Tests/Issue8252ProbeTests.cs b/src/HotChocolate/Data/test/Data.EntityFramework.Tests/Issue8252ProbeTests.cs
new file mode 100644
index 00000000000..905f6b2f670
--- /dev/null
+++ b/src/HotChocolate/Data/test/Data.EntityFramework.Tests/Issue8252ProbeTests.cs
@@ -0,0 +1,295 @@
+using System.Text.Json;
+using HotChocolate.Execution;
+using HotChocolate.Execution.Processing;
+using HotChocolate.Types;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace HotChocolate.Data;
+
+public sealed class Issue8252ProbeTests
+{
+    [Fact]
+    public async Task Union_Subset_With_OffsetPaging_Should_Project_Text_Items()
+    {
+        // arrange
+        var dbFile = System.IO.Path.Combine(
+            System.IO.Path.GetTempPath(),
+            $"issue8252-{Guid.NewGuid():N}.db");
+        var connectionString = $"Data Source={dbFile}";
+
+        try
+        {
+            await using var services = new ServiceCollection()
+                .AddDbContext<Issue8252Context>(b => b.UseSqlite(connectionString))
+                .AddGraphQL()
+                .AddQueryType<Issue8252Query>()
+                .AddFiltering()
+                .AddProjections()
+                .AddUnionType<PostContent>()
+                .AddType<TextContent>()
+                .AddType<ImageContent>()
+                .ModifyRequestOptions(o => o.IncludeExceptionDetails = true)
+                .Services
+                .BuildServiceProvider();
+
+            await using (var scope = services.CreateAsyncScope())
+            {
+                await using var context = scope.ServiceProvider.GetRequiredService<Issue8252Context>();
+                await context.Database.EnsureCreatedAsync();
+
+                context.Content.AddRange(
+                    new TextContent
+                    {
+                        Discriminator = "TEXT",
+                        Id = Guid.NewGuid(),
+                        Text = "Hello World"
+                    },
+                    new ImageContent
+                    {
+                        Discriminator = "IMAGE",
+                        Id = Guid.NewGuid(),
+                        ImageUrl = "http://someurl",
+                        Height = 10
+                    });
+
+                await context.SaveChangesAsync();
+            }
+
+            var executor = await services
+                .GetRequiredService<IRequestExecutorProvider>()
+                .GetExecutorAsync();
+
+            // act
+            var allFragments = await executor.ExecuteAsync(
+                """
+                {
+                  contents {
+                    nodes {
+                      ... on ImageContent {
+                        imageUrl
+                      }
+                      ... on TextContent {
+                        text
+                      }
+                    }
+                  }
+                }
+                """);
+
+            var textOnly = await executor.ExecuteAsync(
+                """
+                {
+                  contents {
+                    nodes {
+                      ... on TextContent {
+                        text
+                      }
+                    }
+                  }
+                }
+                """);
+
+            var textOnlyWithTypeName = await executor.ExecuteAsync(
+                """
+                {
+                  contents {
+                    nodes {
+                      __typename
+                      ... on TextContent {
+                        text
+                      }
+                    }
+                  }
+                }
+                """);
+
+            // assert
+            var allFragmentsResult = allFragments.ExpectOperationResult();
+            Assert.Empty(allFragmentsResult.Errors ?? []);
+
+            var textOnlyResult = textOnly.ExpectOperationResult();
+            var textOnlyWithTypeNameResult = textOnlyWithTypeName.ExpectOperationResult();
+
+            Assert.Empty(textOnlyResult.Errors ?? []);
+            Assert.Empty(textOnlyWithTypeNameResult.Errors ?? []);
+
+            Assert.True(HasTextItem(textOnlyResult.ToJson()), textOnlyResult.ToJson());
+            Assert.True(
+                HasTextItem(textOnlyWithTypeNameResult.ToJson()),
+                textOnlyWithTypeNameResult.ToJson());
+        }
+        finally
+        {
+            if (File.Exists(dbFile))
+            {
+                File.Delete(dbFile);
+            }
+        }
+    }
+
+    private static bool HasTextItem(string resultJson)
+    {
+        using var document = JsonDocument.Parse(resultJson);
+        var items = document.RootElement.GetProperty("data")
+            .GetProperty("contents")
+            .GetProperty("nodes");
+
+        foreach (var item in items.EnumerateArray())
+        {
+            if (item.ValueKind is JsonValueKind.Object
+                && item.TryGetProperty("text", out var text)
+                && text.ValueKind is JsonValueKind.String
+                && text.GetString() == "Hello World")
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    [Fact]
+    public async Task Union_Subset_With_AsSelector_Should_Project_Text_Items()
+    {
+        // arrange
+        var dbFile = System.IO.Path.Combine(
+            System.IO.Path.GetTempPath(),
+            $"issue8252-selector-{Guid.NewGuid():N}.db");
+        var connectionString = $"Data Source={dbFile}";
+
+        try
+        {
+            await using var services = new ServiceCollection()
+                .AddDbContext<Issue8252Context>(b => b.UseSqlite(connectionString))
+                .AddGraphQL()
+                .AddQueryType<Issue8252AsSelectorQuery>()
+                .AddFiltering()
+                .AddUnionType<PostContent>()
+                .AddType<TextContent>()
+                .AddType<ImageContent>()
+                .ModifyRequestOptions(o => o.IncludeExceptionDetails = true)
+                .Services
+                .BuildServiceProvider();
+
+            await using (var scope = services.CreateAsyncScope())
+            {
+                await using var context = scope.ServiceProvider.GetRequiredService<Issue8252Context>();
+                await context.Database.EnsureCreatedAsync();
+
+                context.Content.AddRange(
+                    new TextContent
+                    {
+                        Discriminator = "TEXT",
+                        Id = Guid.NewGuid(),
+                        Text = "Hello World"
+                    },
+                    new ImageContent
+                    {
+                        Discriminator = "IMAGE",
+                        Id = Guid.NewGuid(),
+                        ImageUrl = "http://someurl",
+                        Height = 10
+                    });
+
+                await context.SaveChangesAsync();
+            }
+
+            var executor = await services
+                .GetRequiredService<IRequestExecutorProvider>()
+                .GetExecutorAsync();
+
+            // act
+            var textOnlyWithTypeName = await executor.ExecuteAsync(
+                """
+                {
+                  contents {
+                    ... on TextContent {
+                      text
+                    }
+                  }
+                }
+                """);
+
+            // assert
+            var result = textOnlyWithTypeName.ExpectOperationResult();
+            Assert.Empty(result.Errors ?? []);
+
+            using var document = JsonDocument.Parse(result.ToJson());
+            var contents = document.RootElement
+                .GetProperty("data")
+                .GetProperty("contents");
+
+            var hasText = false;
+            foreach (var item in contents.EnumerateArray())
+            {
+                if (item.ValueKind is JsonValueKind.Object
+                    && item.TryGetProperty("text", out var text)
+                    && text.ValueKind is JsonValueKind.String
+                    && text.GetString() == "Hello World")
+                {
+                    hasText = true;
+                }
+            }
+
+            Assert.True(hasText, result.ToJson());
+        }
+        finally
+        {
+            if (File.Exists(dbFile))
+            {
+                File.Delete(dbFile);
+            }
+        }
+    }
+
+    public sealed class Issue8252Query
+    {
+        [UsePaging]
+        [UseProjection]
+        [UseFiltering]
+        public IQueryable<PostContent> GetContents(Issue8252Context database)
+            => database.Content;
+    }
+
+    public sealed class Issue8252AsSelectorQuery
+    {
+        public IQueryable<PostContent> GetContents(
+            Issue8252Context database,
+            ISelection selection)
+            => database.Content.Select(selection.AsSelector<PostContent>());
+    }
+
+    public class PostContent
+    {
+        public Guid Id { get; set; }
+
+        public required string Discriminator { get; set; }
+    }
+
+    public sealed class TextContent : PostContent
+    {
+        public required string Text { get; set; }
+    }
+
+    public sealed class ImageContent : PostContent
+    {
+        public required string ImageUrl { get; set; }
+
+        public int Height { get; set; }
+    }
+
+    public sealed class Issue8252Context(DbContextOptions<Issue8252Context> options) : DbContext(options)
+    {
+        public DbSet<PostContent> Content => Set<PostContent>();
+
+        protected override void OnModelCreating(ModelBuilder builder)
+        {
+            builder.Entity<PostContent>().HasKey(e => e.Id);
+            builder.Entity<PostContent>()
+                .HasDiscriminator(e => e.Discriminator)
+                .HasValue<TextContent>("TEXT")
+                .HasValue<ImageContent>("IMAGE");
+        }
+    }
+}
diff --git a/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/Issue8252UnionProjectionTests.cs b/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/Issue8252UnionProjectionTests.cs
new file mode 100644
index 00000000000..f9108c45121
--- /dev/null
+++ b/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/Issue8252UnionProjectionTests.cs
@@ -0,0 +1,231 @@
+using HotChocolate.Execution;
+using HotChocolate.Types;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Squadron;
+
+namespace HotChocolate.Data;
+
+[Collection(PostgresCacheCollectionFixture.DefinitionName)]
+public sealed class Issue8252UnionProjectionTests(PostgreSqlResource resource)
+{
+    [Fact]
+    public async Task Union_AllFragments_With_OffsetPaging_Should_Project()
+    {
+        // arrange
+        var (executor, _) = await CreateExecutorAsync();
+
+        // act
+        var result = await executor.ExecuteAsync(
+            """
+            {
+              contents {
+                items {
+                  ... on TextContent {
+                    text
+                  }
+                  ... on ImageContent {
+                    imageUrl
+                  }
+                }
+              }
+            }
+            """);
+
+        // assert
+        var operationResult = result.ExpectOperationResult();
+        Assert.Empty(operationResult.Errors ?? []);
+
+        result.MatchInlineSnapshot(
+            """
+            {
+              "data": {
+                "contents": {
+                  "items": [
+                    {
+                      "imageUrl": "https://example.com/photo.jpg"
+                    },
+                    {
+                      "text": "Hello World"
+                    }
+                  ]
+                }
+              }
+            }
+            """);
+    }
+
+    [Fact]
+    public async Task Union_SingleFragment_With_OffsetPaging_Should_Project()
+    {
+        // arrange
+        var (executor, _) = await CreateExecutorAsync();
+
+        // act
+        var result = await executor.ExecuteAsync(
+            """
+            {
+              contents {
+                items {
+                  ... on TextContent {
+                    text
+                  }
+                }
+              }
+            }
+            """);
+
+        // assert
+        var operationResult = result.ExpectOperationResult();
+        Assert.Empty(operationResult.Errors ?? []);
+
+        result.MatchInlineSnapshot(
+            """
+            {
+              "data": {
+                "contents": {
+                  "items": [
+                    null,
+                    {
+                      "text": "Hello World"
+                    }
+                  ]
+                }
+              }
+            }
+            """);
+    }
+
+    [Fact]
+    public async Task Union_TypenameWithFragment_With_OffsetPaging_Should_Project()
+    {
+        // arrange
+        var (executor, _) = await CreateExecutorAsync();
+
+        // act
+        var result = await executor.ExecuteAsync(
+            """
+            {
+              contents {
+                items {
+                  __typename
+                  ... on TextContent {
+                    text
+                  }
+                }
+              }
+            }
+            """);
+
+        // assert
+        var operationResult = result.ExpectOperationResult();
+        Assert.Empty(operationResult.Errors ?? []);
+
+        result.MatchInlineSnapshot(
+            """
+            {
+              "data": {
+                "contents": {
+                  "items": [
+                    {
+                      "__typename": "ImageContent"
+                    },
+                    {
+                      "__typename": "TextContent",
+                      "text": "Hello World"
+                    }
+                  ]
+                }
+              }
+            }
+            """);
+    }
+
+    private async Task<(IRequestExecutor Executor, ServiceProvider Services)> CreateExecutorAsync()
+    {
+        var db = "db_" + Guid.NewGuid().ToString("N");
+        var connectionString = resource.GetConnectionString(db);
+
+        var services = new ServiceCollection()
+            .AddDbContext<Issue8252Context>(c => c.UseNpgsql(connectionString))
+            .AddGraphQLServer()
+            .AddQueryType<Issue8252Query>()
+            .AddUnionType<PostContent>()
+            .AddType<TextContent>()
+            .AddType<ImageContent>()
+            .AddProjections()
+            .AddFiltering()
+            .ModifyRequestOptions(o => o.IncludeExceptionDetails = true)
+            .Services
+            .BuildServiceProvider();
+
+        await using var scope = services.CreateAsyncScope();
+        var context = scope.ServiceProvider.GetRequiredService<Issue8252Context>();
+        await context.Database.EnsureCreatedAsync();
+
+        context.Content.AddRange(
+            new TextContent
+            {
+                Id = Guid.NewGuid(),
+                Discriminator = "TEXT",
+                Text = "Hello World"
+            },
+            new ImageContent
+            {
+                Id = Guid.NewGuid(),
+                Discriminator = "IMAGE",
+                ImageUrl = "https://example.com/photo.jpg",
+                Height = 600
+            });
+
+        await context.SaveChangesAsync();
+
+        var executor = await services
+            .GetRequiredService<IRequestExecutorProvider>()
+            .GetExecutorAsync();
+
+        return (executor, services);
+    }
+
+    public sealed class Issue8252Query
+    {
+        [UseOffsetPaging]
+        [UseProjection]
+        [UseFiltering]
+        public IQueryable<PostContent> GetContents(Issue8252Context context)
+            => context.Content;
+    }
+
+    public class PostContent
+    {
+        public Guid Id { get; set; }
+
+        public required string Discriminator { get; set; }
+    }
+
+    public sealed class TextContent : PostContent
+    {
+        public required string Text { get; set; }
+    }
+
+    public sealed class ImageContent : PostContent
+    {
+        public required string ImageUrl { get; set; }
+
+        public int Height { get; set; }
+    }
+
+    public sealed class Issue8252Context(DbContextOptions<Issue8252Context> options) : DbContext(options)
+    {
+        public DbSet<PostContent> Content => Set<PostContent>();
+
+        protected override void OnModelCreating(ModelBuilder builder)
+        {
+            builder.Entity<PostContent>().HasKey(e => e.Id);
+            builder.Entity<PostContent>()
+                .HasDiscriminator(e => e.Discriminator)
+                .HasValue<TextContent>("TEXT")
+                .HasValue<ImageContent>("IMAGE");
+        }
+    }
+}
diff --git a/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/__snapshots__/IntegrationTests.CreateSchema.graphql b/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/__snapshots__/IntegrationTests.CreateSchema.graphql
index a6ec08f1e3c..36c595f7c69 100644
--- a/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/__snapshots__/IntegrationTests.CreateSchema.graphql
+++ b/src/HotChocolate/Data/test/Data.PostgreSQL.Tests/__snapshots__/IntegrationTests.CreateSchema.graphql
@@ -146,15 +146,27 @@ type ProductEdge @shareable {
 
 type ProductType {
   id: Int!
-  name: String!
   products: [Product!]!
 }
 
+type ProductTypeConnection @shareable {
+  edges: [ProductTypeEdge!]!
+  nodes: [ProductType!]!
+  pageInfo: ConnectionPageInfo!
+  totalCount: Int! @cost(weight: "10")
+}
+
+type ProductTypeEdge @shareable {
+  node: ProductType!
+  cursor: String!
+}
+
 type Query {
   "Fetches an object given its ID."
   node("ID of the object." id: ID!): Node @lookup @shareable @cost(weight: "10")
   "Lookup nodes by a list of IDs."
   nodes("The list of node IDs." ids: [ID!]!): [Node]! @shareable @cost(weight: "10")
+  hiddenNameProductTypes("Returns the first _n_ elements from the list." first: Int "Returns the elements in the list that come after the specified cursor." after: String "Returns the last _n_ elements from the list." last: Int "Returns the elements in the list that come before the specified cursor." before: String where: ProductTypeFilterInput @cost(weight: "10") order: [ProductTypeSortInput!] @cost(weight: "10")): ProductTypeConnection! @listSize(assumedSize: 50, slicingArguments: [ "first", "last" ], slicingArgumentDefaultValue: 10, sizedFields: [ "edges", "nodes" ], requireOneSlicingArgument: false) @cost(weight: "10")
   brands("Returns the first _n_ elements from the list." first: Int "Returns the elements in the list that come after the specified cursor." after: String "Returns the last _n_ elements from the list." last: Int "Returns the elements in the list that come before the specified cursor." before: String where: BrandFilterInput @cost(weight: "10")): BrandConnection! @listSize(assumedSize: 50, slicingArguments: [ "first", "last" ], slicingArgumentDefaultValue: 10, sizedFields: [ "edges", "nodes" ], requireOneSlicingArgument: false) @cost(weight: "10")
   brandById(id: ID!): Brand @lookup @cost(weight: "10")
   brandByIdWithDL(id: ID!): Brand @lookup @cost(weight: "10")
@@ -237,9 +249,7 @@ input ProductFilterInput {
   description: StringOperationFilterInput
   price: DecimalOperationFilterInput
   imageFileName: StringOperationFilterInput
-  typeId: IntOperationFilterInput
   type: ProductTypeFilterInput
-  brandId: IntOperationFilterInput
   brand: BrandFilterInput
   availableStock: IntOperationFilterInput
   restockThreshold: IntOperationFilterInput
@@ -256,10 +266,13 @@ input ProductTypeFilterInput {
   and: [ProductTypeFilterInput!]
   or: [ProductTypeFilterInput!]
   id: IntOperationFilterInput
-  name: StringOperationFilterInput
   products: ListFilterInputTypeOfProductFilterInput
 }
 
+input ProductTypeSortInput {
+  id: SortEnumType @cost(weight: "10")
+}
+
 input StringOperationFilterInput {
   and: [StringOperationFilterInput!]
   or: [StringOperationFilterInput!]