IOS 15.4 + Firebase Crash

Hi, We've been getting reports of our app crashing on startup. We had a hard time understanding the issue due to lack of data. We were able to get a crash report from a device that is consistently experiencing the crash:

We do not have access to the device and we are unable to reproduce this crash in a DEV environment. We tried upgrading Xcode and Firebase as recommended in this thread:

https://forum.unity.com/threads/ios-15-crash-since-2nd-sessions-xcode-13.1178734

We use Unity 2020.3 do develop the app. Any help would be welcome,

ty.

IOS 15.4 + Firebase Crash
 
 
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