iOS Undo crash - How to interpret back trace?

I'm trying to debug the backtrace from Crashalytics. It happening in the undo block. Does anyone know how to interpret the exception on "obc_opt_class" and "swift_getObjectType"?

0 libobjc.A.dylib 0x199e3008c objc_opt_class + 16 1 libswiftCore.dylib 0x189285128 swift_getObjectType + 64 2 libswiftFoundation.dylib 0x188d8f7fc thunk for @escaping @callee_guaranteed (@in_guaranteed Any) -> () + 40 3 Foundation 0x186660af0 -[_NSUndoStack popAndInvoke] + 188 4 Foundation 0x18665e6ec -[NSUndoManager undoNestedGroup] + 292

iOS Undo crash - How to interpret back trace?
 
 
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