What worked for me was completely removing the user from the app and then adding them again. I did this by deleting the group they were in and selecting "remove completely from app". This will remove them from any other group that they were added to. After that I created a new group and added them in as new tester.

Yes currently facing the same issue but we are using Xcode cloud which uses Xcode 15.0.1 (15A507).