cancelInteractiveMovement() seems broken

[halst]

Cells should return to original positions, but some are missing or inconsistent with model. This seems to be on Apple's end; can you confirm?
To reproduce: call cancelInteractiveMovement() on gesture .Ended instead of endInteractiveMovement(). Wrapping in performBatchUpdates w/ reload in completion almost fixes, but not quite always.

[github-user32]

I've seen similar things with cancelInteractiveMovement() too on iOS 9.2. My workaround at the moment is to call collectionView.reloadItemsAtIndexPaths(collectionView.indexPathsForVisibleItems()) immediately afterwards which sometimes causes a slightly ugly re-shuffle, but at least the resulting cells reflect the model accurately. Be interested to hear if a better solution is known.