Crashlytics shows large number of crashes on iPhone Xs Max

Question

I am working on an iPhone app which already has approx thousands of active users across globe. The app already has crashlytics integrated. Previously the app has CoreData related issues, which used to get reported on crashlytics and those issues state that the crash occurred in CoreData related class. But recently I am getting a frequent crash from a user who has iPhone Xs Max. The error does not have much detail, which could be helpful. The crash shows this stack

0 libsystem_platform.dylib 0x1b3bdbf64 os_unfair_lock_lock + 16

1 CoreFoundation 0x1b3da9bc4 -[__NSDictionaryM

dealloc] + 76 2 (Missing) 0x7c1b7c81b3c0a400

(Missing) 3 (Missing) 0x0 (Missing) 4 (Missing)

0x0 (Missing)

The log shows around 500mb of free ram.

The Crash log looks like this

I've tried in every way but couldn't find the issue. I have many phones but not iPhone Xs Max. All tests go bug free and crash free.

Please Let me know if anyone of you observing same thing in latest iPhones and have found any solution.