As of iOS 9, and in an old iOS 8.3 beta seed (12F5047f), but not the GM version of iOS 8.3, I often see crashes when using NSFetchedResultsController fetchedObjects. For example, when creating an NSSet from them or filtering them with an NSPredicate it often crashes. In both of these cases the code is running from viewDidDisappear but that's probably just a coincidence.My Core Data stack is set up to have a main queue context and private queue context both connected directly to the persistent store coordinator, with changes from the private queue context being merged with mergeChangesFromContextDidSaveNotification (plus a workaround for NSFetchedResultsController when using this setup).Has anyone else been seeing this behavior? I can't get it to reproduce with the debugger attached but it happens frequently with regular usage.