Fixed Bug 59396.

Author: Adit Sheth

src/Http/Http.Extensions/src/DefaultProblemDetailsWriter.cs

@@ -56,7 +56,8 @@ public ValueTask WriteAsync(ProblemDetailsContext context)
         ProblemDetailsDefaults.Apply(context.ProblemDetails, httpContext.Response.StatusCode);
 
         var traceId = Activity.Current?.Id ?? httpContext.TraceIdentifier;
-        context.ProblemDetails.Extensions["traceId"] = traceId;
+        var tradeIdKeyName = _serializerOptions.PropertyNamingPolicy.ConvertName("traceId");
+        context.ProblemDetails.Extensions[traceIdKeyName] = traceId;
 
         _options.CustomizeProblemDetails?.Invoke(context);