Please see my further reply below. Thanks.

Correct. I meant SceneKit, not ARKit. My app also worked perfectly fine on iOS 17. It’s in iOS 18 that ARKit with GameCenter broke.

Gil, the Feedback I opened on Apple FB14697134 is still open. It says that there are less then 10 similar recent reports. So please also open a Feedback on this issue as it seems like this is currently a low priority and only if more Feedbacks will be opened on this, it will have more chances of getting fixed. Thanks.