When a coil fires 3 or 4 times it is telling you that an opto is out.
Your post is a long read you mention standup target and drop target they are not same.If the standup traget is registering properly in switch Edge test then no problem there.Now if the drop target is not popping back up as it should take a look under the play field in that area and might just need a very good cleaning because gunk builds up after years of play.Also clean the coil for the drop target

Not sure if this is your problem, but on my game, I found a broken wire on the front target down switch only after close inspection. At a casual glance, I never would have seen it

my turn to dig up this thread: i'm having the same issue with that target not functionning.
I gave it as close an inspection as I could and found no broken wires nor any suspect mechs. everything "seems" fine.
Only difference is my coil will NOT fire in test mode. nothing happens unless I manually do it from above/under the playfield.

could a coil just fail like that?

thanks for your inputs folks.

I have found is there is no issue typically just activating the the red target in the back of the cabinet / captive ball will let the system know that it’s actually working if it’s not triggered after so many games the system thinks it’s not working and sends an an error/credit dot so the games operator can check it to make sure that it is working correctly typically not hitting the ball hard enough to activate that switch will cause this. just pushing it by hand will tells the system it’s OK and I’ll clear the credit dot! I hope this helps this has cleared a lot of credit dots in all my machines just activating switches that aren’t typically hit or are difficult to hit during regular gameplay can clear up a lot of credit dot issues. Games in private collections don’t get used like they do in arcades and typically switches aren’t hit for quite some time.

Switch error isn't thrown up from time though, it's 90 balls or something like that (30 game equivalent). Usually happens to me on STTNG after a party because no one can hit the borg lock.

There should have been an option in the menus to make it longer or turn it off entirely though. Some games (rollergames) it's annoying because often the top JET lanes don't get hit regardless of what kind of player you are.