From the iOS 15 beta 8 notes, this may help:
Using dispatch semaphores in an iOS app running in a device simulator on a Mac with Apple silicon running macOS 11 will cause the app to crash. (81783378)
Workaround: In Xcode, select Product > Scheme > Edit Scheme, then deselect Run > Options > Queue Debugging > "Enable backtrace recording."
Topic:
Developer Tools & Services
SubTopic:
Xcode
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