Well, in my case, this was the third or forth flight on that particular engine after break-in. And it was not loose. If anything, it was probably to tight and snapped... or it was a defect on the bolt itself. It snapped cleanly right at the base of the threads on one side of the bolt.

I don't know. All I know is that the all-thread bolt is in there and it's been working fine now for about three years.

CGr.