Just picked up a ST pro last night. The ball lock post under the left ramp, in attract mode, will fire up and down for about 5 seconds then stop for a several minutes then do it again. ALSO, during a game, you hit that shot to the left of the demigorgan it will trap the ball, same post lock, but then not release it until the game does a ball search then will release it every time. I did a quick look under the playfield, all connections look good and felt tight. All optos show the red light in that area. I pass an object in front of post opto amd red light goes out. Possible node board issue or transmission board?
Anyone have a similar issue or can direct me to what to look for/check? Still new to fixing these things. I will attempt to clean the opto and adjust it when I get home today.
Not sure if this helps, ive read somewhere I forget where that the pin stadium lights could cause issues. This has the stranger things pin stadium lights as well as the UV kit from stern.

Post in question is in the pic
Thank you in advance!

FED3AC48-E1A8-4847-AC2C-95AD722D26D1 (resized).jpeg

i cleaned the optos the best i could. looked for service alerts, there wasnt any, so then i went in and did a switch test. all switches and optos registered even the post released when a ball went back there, thinking ok cool. then in the middle of the test i threw the ball up the right ramp, the post started to fire randomly, again. then it stopped, and when i threw a ball back there after the post wouldnt release, but the optos registered still. i shut it off to reset it, then did the same process again trying to duplicate the ramp triggering the error. it didnt, a coincidence most likely. i also checked the connections from that side also ok.
i turned it off, then back on, started a game, took the ball and put it back there again, and it did the post rapid fire soon as the ball went back there, then posted a left down post malfunction. then continues the same way only working during ball search.
now its super hard to see back there with the ramp (ill probably have to remove it) but is there a switch the ball sits on after passing the optos against the post?