My workflow has been running tests on iOS 15, 16 and 17 for a long time now, but suddenly it started to fail for iOS 15 and 16. The error does not seem to be code related, since it is a Xcode Cloud failure saying: "Failed to download iOS 16.1 simulator runtime". The exact same issue is showing for iOS 15. It works as expected on iOS 17.
I have also reported this in the Feedback Assistant: FB14855036
If someone knows a work-around for this issue, I'd be happy to hear about it!