Similarly to this old post [https://developer.apple.com/forums/thread/130969] I am getting a "ThreadSanitizer: CHECK failed" before my code seems to have launched. Is this something I should spend time trying to reproduce in a small project or is it an Xcode bug others are getting too?
Turning off the sanitizer is my dirty workaround for now.
I created a blank iOS app project in Xcode, enabled the thread sanitizer and it crashes exactly the same way on two simulators. I'm going to try a few more things to see how much might be me or Xcode.
On my Intel MBP is get a different error when the thread sanitizer is on. "malloc: nano zone abandoned due to inability to preallocate reserved vm space." StackOverflow suggests this is relatively harmless, but paired with the error I get on my Mac Mini (Apple Silicon) There's something afoul. [https://stackoverflow.com/questions/64126942/malloc-nano-zone-abandoned-due-to-inability-to-preallocate-reserved-vm-space]