I believe that may be the result of over tightening at some time. I have been told that over tightening may bend/distort the bolt (or something like that). I did that once and sent it back to have the dodgy part replaced.... that was back when international shipping did not fall into the hands of the greedy Philistines and the two was plane trip was cheaper than a replacement.
My symptoms was actually a slipping bit, however, when discussing with the manufacturer, I was informed that over tightening can cause all sorts of issues... however, they did mention that the level of over tightening would not be an "accidental" occurrence but a concerted effort.
If your first cut is too short... Take the second cut from the longer end... LBD