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Summary:
NSFetchedResultsController has multiple inconsistencies in iOS 9.0 GM that cause UITableView to crash:

1. FRC sends Update before or after Delete which causes UITableView to crash with the following message:

CoreData: error: Serious application error.  An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:.  attempt to delete and reload the same index path (<NSIndexPath: 0xc000000000000016> {length = 2, path = 0 - 0}) with userInfo (null)

2. Any updates cause FRC to send Insert event first, then Update which results in:

CoreData: error: Serious application error.  An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:.  attempt to insert row 1 into section 0, but there are only 1 rows in section 0 after the update with userInfo (null)

3. Move event is often sent instead of update which is not correct. Both old and new indexes are the same in that case.

Apps built against iOS 9.0 GM SDK using FRC behave differently on iOS 8.4 and iOS 9.0 GM. It’s more stable on iOS 9.0 GM and crash pretty often on iOS 8.4.

Steps to Reproduce:

Expected Results:

Actual Results:

Regression:
iOS 9.0 GM is more stable while iOS 8.4 always almost crash.

Notes:
Here is a workaround I used for Xcode 7 beta 6:
http://stackoverflow.com/a/32466951/351305