Update:
I did one more flight:
EDDP-EDDS, Route: GOLAT T202 LASGA DCT BAMAS Z77 AMOSA DCT GEBNO/N0000F100
No issue at this flight, everything worked as it should. I have no idea what is going on. Sometimes it work, sometimes not. I think it is related to
the MSFS, not to the aircraft.
There is also an flight which Emanuel did without any problems.
Cheers, Chris