My Space Invaders is not well. Points are added when they shouldn't be added.

1) Most often 10 points at a time
2) Most often without any sound (although other sounds not related to the point increase can be heard sometimes)
3) It can occur during play, but also immediately after the bonus points or between balls

Video 1: No ball on the playfield
Video 2: When I move the ball over the playfield (very odd)

My first thought was that a switch could be stuck somewhere but I have checked them all, and they aren't.