We're experiencing the same issue with UserDefaults. Only one out of three of our apps is experiencing this issue. The solution introduced by @nickfromnelson did not solve the problem. Our temporary solution was to replace UserDefaults with our implementation for the time being.

We're experiencing the same issue with one of our apps. I'm not sure whether it's related to the Private Relay. Our temporary solution was to replace UserDefaults with our implementation for the time being. Other similar threads: https://developer.apple.com/forums/thread/685685?login=true https://github.com/ionic-team/capacitor-plugins/issues/643

One of our apps is facing the same issue. We've seen a huge spike in the behavior you've described after the iOS 15 launch. Before that, only a small subset of users had problems with that. Sadly, we were unable to find the root cause of the issue. Our temporary solution was to completely replace UserDefaults with our own implementation.

One of our apps is facing the same issue. We've seen a huge spike in the behavior you've described after the iOS 15 launch. Before that, only a small subset of users had problems with that. Sadly, we were unable to find the root cause of the issue. Our temporary solution was to completely replace UserDefaults with our own implementation. Did you manage to solve this issue @craigaps?

This answer solved this issue for us.

This answer solved this issue for us.

In the end, the issue turned out not to be related to Private Relay at all. It was caused by a combination of iOS 15 changes to app startup and app entitlements. See this answer for more info.

Could you elaborate on what you changed? We've changed the Data Protection Entitlement to NSFileProtectionCompleteUntilFirstUserAuthentication which solved the issue for us. Also, are you able to reproduce consistently? Yes, it's easily reproducible. Reproduction steps in our case: Launch the app and log in. Force quit the app. Wait. Somewhere in the next hour or so the prewarming will start, which in resolution will call application(_:didFinishLaunchingWithOptions:). As mentioned previously, in our case, we check for some UserDefaults flags there. If they do not exist then we do a complete cleanup (UserDefaults + Keychain). This caused users on iOS 15 to get logged out.