FWIW we still encounter this issue on 14.5.1. The only way we've been able to avoid the damage is by dispatching async to (non-main) serial dispatch queue.

Hello. We turned our use of this API on today and within a few hours had lots of crashes from the main thread hanging on it. We want to move on this API, but it's not marked as threadsafe (nor does it make sense for it to be, given what it's for) and it causes our app to crash more than 10x as often as it normally would. I also am curious if there are any updates about this API.