The video you posted is of the flipper cabinet switch. That is not the EOS switch. The EOs switch is on the flipper mech itself underneath the playfield. That switch is normally closed. When you press the flipper button in test mode you should hear a beep for when the cabinet switch closes, then another beep when you let go and the eos switch closes again.

Start a game and simply press the snikt and put the ball on the ramp. Does it give you a PF x every time doing that?

If so then your issue is probably the flippers causing another switch to register from vibration.

When you put the slings back together make sure the switch contacts are gapped extra wide. Then play with the glass off and try to hit the snikt from the flippers and see if you can consistently get it.

What could be happening too is your snikt target isn’t sensitive enough so certain shots that are hitting off the target and going up the ramp aren’t actually registering that switch.

Take an alligator clip and pinch the left eos switch shut during switch test. Then do your sling firing. See if that changes anything.

No worries man. I’ve had this EXACT same issue before on a different era of game. But experience and help from people on here has taught me to never trust your eyes when testing switches. Always best to use a meter or jumper it shut to be sure.

Follow the wires back to the connector under the playfield for that opto and see if any wires are loose. Re-seat the connector and see if that helps. Also, when testing switches, use the ball, not your finger.

Could be that the opto is bad and needs replaced though.

Make sure the optos are centered in their holes in the ramp. Make sure there’s no debris in the holes. Reflow the solder on the wires on the optos.

Call stern and get replacement optos if none of that works.

Can’t be, or else everyone would have the issue.