Appreciate your followup. I would like to ask everyone to check your troubleshooting workflow.
During the troubleshooting process, it’s natural for players to log into Zwift from multiple computers to see if the problem is related to the specific OS platform as you’re describing.
If you leave one session open when you log into the second (or third!) - it confuses the game server as which device you intend to use, and weird symptoms like BLE dropouts, and random-feeling resistance changes will surface.
So - would you try this ?
Save & upload (or trashcan) any open sessions If you want to be sure, power off any computers you don’t intend to use for testing step 6.
On iOS / Android / Apple TV - swiping Zwift into the background does NOT terminate a session. To exit the app completely, you must either save & upload or trashcan your session.
Wait at least 2 minutes after closing all instances of Zwift - this timeout gives the server a chance to determine which device you intend to use.
While you’re waiting those 2 minutes - please manually update to the most recent version of Zwift iOS. Particularly on iOS - if you’ve set your App Store preference to not auto-update, you may be on an outdated build.
Power cycle your KICKR while you’re at it.
Fire up Zwift on your iOS device. Pair the KICKR as a power source first and then as a controllable signal.
Does that clear the issue? We’d especially like to know if it’s resolved if you’re on Wahoo’s v4.21 firmware.