Reverted previous fix.

Code/Framework/AzCore/AzCore/Serialization/Json/JsonDeserializer.cpp

@@ -33,6 +33,11 @@ namespace AZ
                 "Target object for Json Serialization is pointing to nothing during loading.");
         }
 
+        if (IsExplicitDefault(value))
+        {
+            return context.Report(Tasks::ReadField, Outcomes::DefaultsUsed, "Value has an explicit default.");
+        }
+
         BaseJsonSerializer* serializer = context.GetRegistrationContext()->GetSerializerForType(typeId);
         if (serializer)
         {