Seems like any time you have a rope that can slide across a piece of metal, it can potentially happen. That morning it was doing it, I had a huge tether lead, on the ground, in a leaning tree. When I tried to replicate it under a normal situation, seems it takes a lot of work to get the rope all the way to the side of the D ring. I think the little dab of wax made a big difference. I can still get it to do it if I force it. But i feel it more than I hear it.