There is an adjustment called "Game Restart" if you have any credits in and you are on your first ball and the start button is pressed it will restart your game. I believe there are three settings "Never", "Slow" and "Immediate" turn it to never it sounds like your switch problem activates the start button and restarts your game and by turning it of it will not restart the game. I would give that a try if your problem goes away then I would say for sure it is a matrix problem somewhere but at least you will be able to play without restarts.
