I had a NGG that had an insert that had raised up maybe 1/16in on one side but it was enough to affect the ball. When pushed back down it made a slight plastic like lip that again would affect the ball. I just lived with it until later selling the game but I'm curious if anyone know how to resolve such an issue. I thought about using a heat gun or the edge of a soldering iron to slightly heat the raised area to try and get it to shrink back.