Hi Dave,
during my last flight from LTBU to LBSZ center handed me over to approach, approach to tower and tower to ground. But LBSZ has no approach, no tower and no ground frequency. As fas as I know this never happend with the previous version 2.11.
Best regards
Wolfgang
PS: Do you have an idea about the cyclic frequency change between approach and center? I know you have to look to many log files from the others also. But in the meantime this happens on every flight.