This is the follow-up ticket of
TIMOB-27053. That ticket fixed some critical issues in regards to JSCore crashes, but now we still see a lot (on older iPhones every time) dead locks that cause the app to freeze and crash later. The worst thing is that those logs also do not show up on Crashlytics, so cannot know exactly where it crashes, although I assume it is JSCore as well.
Notable is that before every crash, it shows the following warning:
As discussed with Jan Vennemann, this is likely the reason why it crashes - a deadlock in firing the event. Unfortunately he was not able to provide a workaround or fix to test so far, so we are escalating this ticket now.