Piston piece

I doubt it was ring butting if it was only that one hole, and only that one chip. But, it IS possible. Detonation can also do that. If it were me, I would not run it like that. The broad side fot he ring is not supposed to be exposed to combustion gasses and the ring seal in that cylinder will be... odd at best I think. Pull a piston and measure the ring gap. If it's less than .021 and that's a KB hyper, the rings butted.