Quoted from MikeS:
My crossbow did that when I first got the game and it was a matter of adjusting the two switches on the Crossbow. Took a bit of trial and error to get it to work just right but it hasn't given me an issue since. Back when it didn't work I'd get super frustrated but now I've grown to really like the crossbow! Way more satisfying than just shooting the shot with the flippers.
It worked for like 6 or more months and was never really very satisfying... but maybe I need a plastic crossbow on top to get the full effect. Mostly just seems to slow the game down. Even more so when it hasn’t worked the last week or so.