Quoted from Legenbad:Unplugging the opto harness and plugging it back in seemed to resolve this for me. Can you shed some light on your reasoning behind doing this? Just trying to learn!
Sometimes things get knocked around and loosen up. I’ve seen a few of my strange issues on various machines resolved by resetting the cables at the trough area. If the issue persists may not be a bad idea to pull the opto board and reflow the solder joints on the pcb connectors.
Also, if you use a shaker in your machine. Not a bad idea to lift the table up every once in a while to check cable connections and make sure everything is secure.