Does the endless rotating occur even if no drop targets are knocked down? I had a very similar problem with my Jumping Jack. After losing a ball, if no drop targets were downed it would kick the ball out and play correctly, but if one or more drop targets were down, the machine would endlessly cycle. I could flick the ball out by hand and it would stop running and step up to the next ball. Turned out to be the spring tab snow shoes on the bonus unit weren't exactly lined up with the rivets. I cleaned and realigned and the problem went away.

Forgot to mention... If this is still happening when no drop targets are down then the problem probably isn't in the bonus unit. It only searches for a bonus if at least one target is down. If no targets are down it shouldn't run at all and quickly kick the ball out. If this is the case you would need to look for what is telling the bonus unit to activate. As Dogman said, possibly a drop target switch.

I couldn't get your video to play last night but it worked today. Scratch the bonus unit idea. It is searching for bonus even with the targets up. Just need to find what all activates that bonus. I'll try to locate my schematic and see if I can come up with something. In the meantime I would clean and adjust every switch within the "add bonus" path. That's probably a lot or switches, but it's worth doing to eliminate all them as a possibility.

Just looked at my Jumping Jack and it does not have that jumper on the F relay. But, since yours has always been there and it used to work, it's probably not what's causing your current issue.