Yes, I meant a field named "Properties", which could have been on another Integrity Server your client connected to. The client tends to save preferences such as what fields were visible in a given view. If you were to use that same viewset and connected to a different server, the client could throw that error because FieldX does not actually exist on that other environment.
If you check the IntegrityClient.log file with DEBUG logging enabled, you may see some more details about what is requesting that field data. The Integrity Client log is normally found in C:\Program Files (x86)\Integrity\IntegrityClient10\bin\