iOS (iPAD) + Wahoo kickr core: Zwift does not use SIM mode during free ride/race. It stucks somehow in ERG mode

Hi, since latest ZWIFT release, I’ve huge issue with my kickr core.
After connection the kickr seems to be in ERG mode, either at 60W or 120W.
If I start a workout, everything behaves correctly. But after leaving the workout zwift just does not use sim mode.
Even if ZWIFT is restarted and a free ride is started, it’s mostly the same.
Only several restart attempts, with repowering the kickr (in connection window) seems to solve the issue, until ZWIFT is started the next time.

If I use the wahoo app with this ipad, everything is fine - erg, resistance, simulation.

best regards
Bastian