Nice find. Funny when it's something mechanical when our first thought is to look electronic.

How did you get the magnet core level exactly? I have the same issue. Mine is flush at the front and has a small lip on the back so i cant raise up the whole magnet core or there will be a lip at the front.

maybe ill stick in a couple thin washers under the lower end and then adjust the whole core

What I did (incase anyone else has a similar issue) is to turn the magnet assembly 180 degrees so now the small lip is at the front and the core is flush at the back (nearest the doors). Since the small lip is at the front and the magnet is flush at the back now there does not appear to be anymore ball jumping the opto. Easy to do. Remove 4 screws and turn 180 and screw back in. Not sure if this affects any of the magnet software programming but tested it a bunch and seems no different so far.

I believe this small lip is slight wear to the magnet edge itself from years of play.