Just upgraded my ipadOS app to iOS15 and the AR part of the app is now completely broken. Literally no AR functionality works. Other than that, an awesome upgrade;) I verified I'm not crazy by installing the same app to iPad8 running iOS14.8 and my AR functionality works fine.
broken environment: xcode13, ios15 (prod release), iPadPro working environment: xcode13, ios14.8, iPad8
I think this is worth a zoom meeting to demo my findings with the apple dev team.