I am using a zwitft hub. Recently upgraded to the latest firmware (5.2.2). Also upgraded tvOS to the latest Zwift SW (1.5).
When I tested zwitfing after that I noticed that I had to spin much faster on the highest gear than I used to … (when not in ErgMode).
After some research I noticed that “virtual shitfing” was set to “enabled” even if I did not have any Zwift play or click controllers.
Disabled “virtual shitfing” and then it worked just fine again.