After the upgrade to 11.7.4 (SP1), class derived from a base class with a HANDLE as one of the properties is displaying a CAST error for the HANDLE property when saving in PDSOE. It looks as though the save is completing but I can't be sure what ends up missing. I think it is trying to serialize the property into the class definition of the derived class, and it is not able to do so. Unmodified base class property serialization into the derived class definition is an existing issue, but it's not as detrimental as not being able to save (or at least questionable state after a save).