So when I started a new game tonight, on ball 1, all balls were kicked out and stacked in the shooter lane. Powered off and drained balls, powered on and started game and one ball into shooter lane, no problem. During the game, ball went into trunk to start illusion and was kicked out of the trap door, after a two second longer pause then usual. However, after ejecting the ball, the trap door kept opening and closing on its own; no balls were locked in the trough. I looked underneath to find the rubber grommet finally failed on the trap door plunger, but I can't imagine that could be part of the issue.
Right now, these problems are intermittent. I've gone through an entire game since it first happened without either problem, but the trap door issue is becoming a regular thing. Any ideas where to start?

EDIT: Resolved. The optos for the trough were filthy and LEDs just needed a clean. Switch test checks out. Got lucky

EDIT to the EDIT: After a few games with no issues, the balls started stacking again in the shooter lane. Arrgh! Any suggestions? Go ahead and replace trough optos?

Thanks! I reseated the connectors and untangled some possible wires touching on and around the Hocus Pocus switch after I ultimately got a Gnd Short Row 1 is Stuck Closed message. That seemed to do it.