Quoted from rosh:You should also be checking the switch on the right spinner relay vs the spinner itself. I have found that if the spinner itself is an 'closed' state other aspects of the game will not behave correctly.
Thats a good idea rosh. I own the game with him and that right spinner has stuck closed before. Also the 500 point relay is activating when the problem occurs. It does not activate when advance left bonus is lit but does when the right is. The switch controlling the left and right is the match switch in the back box. No scoring comes from that stepper though.