I am facing same problem after iOS 14.0 version(build with xcode 12). See my crash log
Crashed: NSManagedObjectContext 0x283348410
0	CoreData											 0x1a9b1ba6c _PFObjectIDFastHash64 + 36
1	CoreFoundation								 0x1a3cd8aa8 __CFBasicHashRehash + 996
2	CoreFoundation								 0x1a3cdc790 CFBasicHashRemoveValue + 2352
3	CoreFoundation								 0x1a3bfa600 CFDictionaryRemoveValue + 224
4	CoreData											 0x1a9a6b390 -[NSManagedObjectContext(_NSInternalAdditions) _forgetObject:propagateToObjectStore:removeFromRegistry:] + 120
5	CoreData											 0x1a9a4aef8 -[_PFManagedObjectReferenceQueue _processReferenceQueue:] + 864
6	CoreData											 0x1a9b63a7c __90-[NSManagedObjectContext(_NSInternalNotificationHandling) _registerAsyncReferenceCallback]_block_invoke + 68
7	CoreData											 0x1a9b5a01c developerSubmittedBlockToNSManagedObjectContextPerform + 156
8	libdispatch.dylib							0x1a38e7280 _dispatch_client_callout + 16
9	libdispatch.dylib							0x1a38c34f0 _dispatch_lane_serial_drain$VARIANT$armv81 + 568
10 libdispatch.dylib							0x1a38c3fdc _dispatch_lane_invoke$VARIANT$armv81 + 404
11 libdispatch.dylib							0x1a38cd800 _dispatch_workloop_worker_thread + 692
12 libsystem_pthread.dylib				0x1ec3e35a4 _pthread_wqthread + 272
13 libsystem_pthread.dylib				0x1ec3e6874 start_wqthread + 8
iOSDev_Atek
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