Session failed with" Caught exception in CanPierFlipNow"

Thank you very much Ken for the detailed analysis! So the conclusion is that the mount somehow caused the issue. That makes sense for the events that happened right after pointing to target 3 (IC2118) but i don't understand all the lines at the beginning of the session with the canpierflipnow exceptions. (The log file shows that i prepared the session around 17:44 and started it at 20:23.)
And i looked for the mount log file.....but logging was not enabeled for the GM2000 ASCOM driver (oops). Have that enabled now.