Yes, I have seen that several times. Restarting couatl fixes it sometimes. Other times, I have to save the flight and restart the sim to get past it.
I turned on logging, but didn't see anything suspicious in it. I don't think it is related to the gate, as I can usually do what I said above to work around it. I think it has something to do with the state of something on the airplane. It's not the doors or the engines. Still investigating.