diff --git a/Jint.Tests.Test262/Test262Test.cs b/Jint.Tests.Test262/Test262Test.cs
index ca642a5683..dca9890f76 100644
--- a/Jint.Tests.Test262/Test262Test.cs
+++ b/Jint.Tests.Test262/Test262Test.cs
@@ -42,10 +42,15 @@ private static Engine BuildTestExecutor(Test262File file, Test262AgentManager? a
             var delay = (int)TypeConverter.ToNumber(args.At(1));
             if (callback is ICallable callable)
             {
-                Task.Run(async () =>
+                _ = Task.Run(async () =>
                 {
                     await Task.Delay(delay);
-                    callable.Call(JsValue.Undefined, Arguments.Empty);
+                    // Queue callback to event loop instead of calling directly from background thread
+                    // to avoid race conditions with concurrent JavaScript execution
+                    engine.AddToEventLoop(() =>
+                    {
+                        callable.Call(JsValue.Undefined, Arguments.Empty);
+                    });
                 });
             }
             return JsValue.Undefined;
diff --git a/Jint.Tests/Runtime/ExecutionConstraintTests.cs b/Jint.Tests/Runtime/ExecutionConstraintTests.cs
index fa761644ef..c8dd513c86 100644
--- a/Jint.Tests/Runtime/ExecutionConstraintTests.cs
+++ b/Jint.Tests/Runtime/ExecutionConstraintTests.cs
@@ -326,7 +326,7 @@ public void ShouldConsiderConstraintsWhenCallingInvoke()
     {
         var engine = new Engine(options =>
         {
-            options.TimeoutInterval(TimeSpan.FromMilliseconds(100));
+            options.TimeoutInterval(TimeSpan.FromMilliseconds(1000));
         });
         var myApi = new MyApi();
 
@@ -337,7 +337,7 @@ public void ShouldConsiderConstraintsWhenCallingInvoke()
         foreach (var callback in dataReceivedCallbacks)
         {
             engine.Invoke(callback.Value, "Data Received #1");
-            Thread.Sleep(101);
+            Thread.Sleep(200);
             engine.Invoke(callback.Value, "Data Received #2");
         }
     }