Quoted from LTG:Loose coil stop. Or broken spring.
LTG : )
This. But also if you moved the flipper bat. shaft up or down while cleaning it, I’ve found binding flippers on this game when the linkages have some new pressure on them. I know they’re the same parts as my other pins but for some reason they seem to be more sensitive on this game for me. See if lifting (pushing up from the bottom) or lowering the clamp and shaft together makes things seem more free swinging. If so, might want to loosen the nut and raise the shaft in the clamp ever so slightly.
That’s been my issue every time one of these doesn’t want to return “home” thus far.