On my pro I was having the same issue and all switches tested good in self-test mode.
I went in and kind of 'yanked' on the wires into the connector on the opto board. They have a stupid design (IMO) where the wire is just pulled in between two pieces of metal to achieve connection. I happened to notice this molex connector would come a little bit loose so I shoved it back on tight.
Between these two things, I haven't had an issue in the last 100 + games.