Weird libobjc.a.dylib objc_msgsend crash

Search anywhere and could not found an answer. I have this issue causing the app to crash on many users.

How many?

MANY!

I can't reproduce the crash and I can't understand anything from the Crashlytics logs:

After reading some questions and answers around I suspect that something in ManagedObjectContext cause it.

Already visited:

1. libobjc.A.dylib objc_msgSend crash occurring with core data usage in background thread

2. Swift Crash libobjc.A.dylib objc_msgSend

3. iOS crash libobjc.A.dylib objc_msgSend

4. Xcode 8.1 release APP crash libobjc.A.dylib objc_msgSend

5. libobjc.A.dylib objc_msgSend crash occurring with core data usage in background thread

What should I do next?

Crash log:

Crashed: com.apple.main-thread
0  libobjc.A.dylib                0x1b0e720f8 objc_msgSend + 24
1  Foundation                     0x19dcb3b90 __NSThreadPerformPerform + 188
2  CoreFoundation                 0x19c89c76c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
3  CoreFoundation                 0x19c89c668 __CFRunLoopDoSource0 + 208
4  CoreFoundation                 0x19c89b9cc __CFRunLoopDoSources0 + 376
5  CoreFoundation                 0x19c895a8c __CFRunLoopRun + 824
6  CoreFoundation                 0x19c89521c CFRunLoopRunSpecific + 600
7  GraphicsServices               0x1b3914784 GSEventRunModal + 164
8  UIKitCore                      0x19f2ce200 -[UIApplication _run] + 1072
9  UIKitCore                      0x19f2d3a74 UIApplicationMain + 168
10 ZoomQuizProd                   0x102a407b0 main + 19 (AppNotificationManager.swift:19)
11 libdyld.dylib                  0x19c5556c0 start + 4