I have this issue. Reported to Zwift Support and acknowledged (eventually).
Same symptoms as described above. I had also posted a separate thread on this forum but this one supersedes.
The problem appears intermittently- less likely to appear if I don’t touch any buttons or hit OK on any of the Zwift notices about steering but it’s not an exact science and hard to replicate consistently.
I run a Kickr Bike with Apple TV.