I'll check.
But first, an interesting update -- after going through diagnostics again, again finding nothing wrong (other than every coil single test firing the loop diverter, I started up a new game, and then spent another minute in frustration pressing the flipper buttons in vain (having the flippers barely twitch while each button press fired the loop diverter) along with the pin trying to kick out ball 1 from the trough by pulsing the loop diverter.... the pin suddenly started working. Played a full game with no issues, and put the ball in each VUK, switch, etc, and everything works.
Divine intervention?
The thing I'm worried about is the root cause is still there lurking, and going to rear its ugly head again in the future.