Noticed that on my WCS, the lane change and assist shot was sporadic or delayed when playing, so I went to check the cabinet flipper optos to see if one was dirty, etc. I noticed that the left flipper has the factory cabinet opto board with the two optos and black plastic interrupter that the flipper button activates, but the right one had what looks like a non-original board with only one opto and some sort of metal interrupter. It looks like the interrupter is clearing the opto, but I'm suspecting this is causing the issues I'm having. Anyone see anything like this before? I would assume I need to put it back to original with one of these (A-17316 per the manual)?

Last pic is the left flipper button.

https://www.thepinballwizard.net/flipper-parts/fliptronics-type-2-flipper-opto-board-assembly-williams/bally-a-17316/

https://www.marcospecialties.com/pinball-parts/A-20207-P
20201109_134137 (resized).jpg20201109_134212 (resized).jpg20201109_134220 (resized).jpg20201109_134416 (resized).jpg

Thanks Lloyd, this got me on the right track. This board/interrupter is not original to the game but does work and register both optos in test separately. I reseated the connector on the opto board and it seems to work consistently now. Pretty anti-climatic but figured I'd close the loop if anyone dug this thread up in the future.