Log4OM

You need to ask the Win4Yaesu or Omnirig programmers about this because the VSP and CAT is their side of things, Log4OM only integrates to Omnirig using a standard command set.

Could also be spurious data originating from the radio

Enable TRACE mode in log, then verify the log.
Informations received and decoded can be verbosely checked in the log in trace mode.