The threaded nut that the cable pinch bolt threads into loses grip on the derailleur 'body', either keeping your from snugging the bolt, or loosening it. We've had 4 of them do this so far. King of annoying. Anyone else? I've only seen it happen on 2 Specialized Roubaixs (or maybe they were Rubies). The other 2, I'm not sure, I wasn't at the shop.