Used to happen to me over 50% of the time. I adjusted the switch.. the switch arm was sticking out too high and was a little firm.. I bent it down so it wasn't taller than the midway point of the pinball. I have less than 2% bounce out, if any.
I wish I could say the same for the lock shot though... I get around 30-40% brick on that. I don't want to take much apart to inspect it though.