diff --git a/src/Docfx.Common/Json/JsonUtility.cs b/src/Docfx.Common/Json/JsonUtility.cs
index 75bf4e427ce..f01a23cd4b5 100644
--- a/src/Docfx.Common/Json/JsonUtility.cs
+++ b/src/Docfx.Common/Json/JsonUtility.cs
@@ -91,9 +91,11 @@ private static bool IsSupported()
             switch (fullName)
             {
                 case "Docfx.Build.Engine.XRefMap":
-                case "Docfx.DataContracts.ManagedReference.PageViewModel":
                     return true;
 
+                case "Docfx.DataContracts.ManagedReference.PageViewModel":
+                    return false; // TODO: Need to support ExtensionData
+
                 // Intermediate types for tests. it's expected to be removed later (And return true by default).
                 case "Docfx.Plugins.MarkdownServiceProperties":
                     return true;
diff --git a/test/docfx.Tests/SerializationTests/YamlSerializationTest.ManagedReference.cs b/test/docfx.Tests/SerializationTests/YamlSerializationTest.ManagedReference.cs
index 3012c8a890f..bbdb31da56b 100644
--- a/test/docfx.Tests/SerializationTests/YamlSerializationTest.ManagedReference.cs
+++ b/test/docfx.Tests/SerializationTests/YamlSerializationTest.ManagedReference.cs
@@ -18,7 +18,7 @@ public void YamlSerializationTest_ManagedReference(string path)
         var model = TestData.Load<PageViewModel>(path);
 
         // Act/Assert
-        ValidateYamlRoundTrip(model);
         ValidateYamlJsonRoundTrip(model);
+        ValidateYamlRoundTripWithJson(model);
     }
 }