the collectionview works fine til some bluetooth device is connected. Than it crashes and only this message comes in the Debugger view.

_createPreparedCellForItemAtIndexPath:withLayoutAttributes:applyAttributes:isFocused:notify:], UICollectionView.m:3964

I use some DecorationView and an own Layout but it creates there. When Bluetooth tastature is disconnected everything is fine. My best guess is that some recognizer is connecting the collectionview and doing weired stuff.