I tried out our AR app for the very first time using iOS 18. It crashed on start.
When I started it in Xcode, the two messages before the crash look like this:
Assert: /Library/Caches/com.apple.xbs/Sources/AppleCV3D/library/VIO/CAPI/src/SlamAnchor.cpp:37 : HasValidPose()
The crashes also occur with the App Store version of our app. The app just crashes after startup. Only the first start seems to be affected, though. Later app starts work fine.
Update: Things are actually worse. The crash occurs every time the app creates a (world) anchor. So this is not something that’s only happening on app start. I just did not try placing new anchors yesterday. The reason why it happened immediately after app start is that we drop some content in the real world at that time, to place a tutorial.
Has anyone else experienced this?
In its current state, our app is completely broken. 
(You can find our app in the App Store as “Marbleverse”.)
I think this is caused by a change in iOS, not by Unity. So I also reported it in the Apple forums as well:
https://developer.apple.com/forums/thread/764425
Yet I am not sure about it. As you can see in the thread, Apple referred me to Unity…