I've been trying to resolve this issue for weeks. It's a full app crash on the IOS version of a react-native app (built with expo). Sentry records the crash as 'Thunk for closure', but with little in the way to go on in terms of breadcrumb or trace.
Sample trace: 
I've seen breadcrumbs for events before the crash of battery level change, orientation change (although app is portrait only). It seems to always occur when the app is brought to the front.
Can anyone help orientate me. I don't see a lot of mention of this error on StackOverflow or elsewhere.
I should also say I'm seeing this in TestFlight. I'm not sure if it survives into app store. It can been 24-30 hours between crashes with 2-3 active test users.
This is an app that's been put into Test Flight. The bug is sporadic and is not seen on simulators.