Pretty experienced with most pins but my doctor who has me a bit stumped this time round. When the left flipper is pressed occasionally the right ball lock coil in time expander is fired. The problem is pretty random but consistant.
Things I have done. Checked all diodes in row, column is all optos. Swapped every single board in game (I own a lot of games so that wasn't difficult) and also the dr who boards all functioned fine in other games. When I say all boards I mean every single board including flipper opto, opto 10 board, everything in back box and coin door board. I'm certain there is a switching issue somewhere. The only switch not tested is switch 48 (select doctor) as I don't have a clue how that works, as the flippers control that. I must add in switch matrix test all switches function perfect and there is no credit dot.
Any thoughts, suggestions or links would be awesome. Thanks in advance to all who reply. Many hours spent on this issue.

Yes of course the select doctor switch, got it. I guess I had been staring at that game too long. Lol
The flipper in switch test does not activate the ball lock opto, only in game play.
I have noticed however that at beginning of game when scrolling though doctors with left flipper it will stop on a doctor and select it as if a ball has been launched, just like normal except I didn't launch the ball and the left flipper caused it. Then either immediately or may take a little bit but it does go into ball search and launches the ball. Scrolling with right flipper does not cause a issue