Lost Sim mode with new Kickr

I started Zwifting on an older Kickr (2016). Everything worked fine, Sim mode and ERG mode. To add another Zwift station I purchased a second, brand new , Kickr two weeks ago. At first it performs well but now I cannot seem to get into SIM mode anymore.
All sensors work well, no interaction of other software, but whenever I start a regular route (no workout) I get no changes in resistance any longer. Sometimes, when I reboot the system a couple of times I am back in sim mode. But the next ride we’re back in to erg mode again. Quite frustrating.
What am I missing? Is there a shortcut to switch from ERG to SIM ?
Thanks a bunch.

ERG mode should only occur when you select workout mode, otherwise it should be “sim” mode. In both cases, at a minimum the Kickr should be paired as the controllable trainer in Zwift. If you don’t have another power source (e.g., Quarq, Vector, Stages, P2Max, etc.,) then, the Kickr should also be paired as the power source in Zwift.

I would double check that everything is paired correctly. Also, make sure you’re paired to the right trainer.

Everything is well paired and working (Zwift reads my heart rate, watts and cadence from the Wahoo sensors). ERG mode works well in structured workouts. But I’m still unable to ride in SIM mode when I’m not in a workout. Every now and then SIM mode does work, but then again, the next five rides it doesn’t.

Is there a shortcut to “reactivate” SIM mode? Is it a common issue on a Mac? (2017 Macbook Pro running High Sierra)

Okay, I found out this is actually a real issue a lot of Zwifters are experiencing. There’s a large thread in the BUGS & SUPPORT section of this forum on this issue in particular.