Game Update 1.39 [May 2023]

There is a separate thread where some users noticed this: KICKR Bike Powerup and U turn buttons don't work [1.34] [April 2023]

However, the original poster was able to get it working again by restarting their device. There are some other users that are experiencing this, and Zwift has not given any recent word as to whether they were able to figure out what is going on.