Yes, movement to friendly provinces should happen first, unless the army coming in is arriving by magic. Are you sure nobody assassinated, seduced, or otherwise interfered with your commander?
Ich might have backups, but I think we'd need agreement from everyone to roll back the turn (if there are indeed backups). After all, someone may have gotten a random event like this, this turn:
I'm just an interloper here, so actually I don't mind rolling back. Easy come easy go
.