Few questions for clarity. Have you confirmed with that user that their iCloud storage is in fact full? When you save the game save a secondary time, are you updating that record, or deleting then saving a new one? Assuming you're using the CKModifyRecordsOperation, how are you handling merge conflicts (i.e. two device scenario race condition).

Is the RevenueCat SDK first party in Flutter for iOS? I'd start with the library developers for your question. You could try using the native swift version of RevenueCat and see if the same problem exists.

Kevin, HealthKit is meant for a single individual, not 'shared'. HealthKit can be used without an Apple ID. It would be just the same as running on a simulator that isn't signed in. That having been said, while you could technically do it, it is overkill and using HealthKit outside of the intended scope. I'll speculate that the built-in pedometer will also not have super reliable results given the way each user walks is different. This is what generates samples for HealthKit under the hood. If you're going to pursue this concept, I would instead recommend using the CMPedometer API directly, which allows for up to 7-days of historical data.

It is referenced in this video to in fact use ASWebAuthenticationSession but I haven't found any useful information in the documentation on how to get it setup with the callback yet: https://developer.apple.com/videos/play/wwdc2020/10174/?time=909

I just received access to the beta. I'm encountering the same issue. I created this feedback: FB9799246 If you create your own feel free to mention so Apple can link as related.