Quoted from PinRetail:

So, the mechanism that smacks the ball is compromised (flattened). Marco sells a replacement part:
https://www.marcospecialties.com/pinball-parts/A-8247
The pivot point with the shaft that this part rotates on is actually one of the only places you put a drop of oil. I've found these mechanisms can be very stiff due to lack of oil. I remove the assembly from the bottom of the playfield, take it apart, clean the old grease off, and apply fresh oil. Sometimes the shaft this rubs on is deeply grooved due to wear, and it needs to be replaced, but frequently oiling this appropriately works good.
Because this is an Addams Family, and Addams Family pinballs have generally had a LOT of work through the years, the spring on this assembly might have been replaced with a spring that is too weak. In the picture everything looks correct, but this assembly uses a quite stiff spring, and a lighter spring doesn't apply nearly enough 'smack' to the ball. I don't think this is your problem.
For other pinballs, you need to make sure that the part is actually hitting the ball squarely, because on other pinballs they don't get enough play to flatten the end. Your assembly looks properly aligned.
Finally, on the top of the playfield there is a little metal extension that 'curls' the ball back to the shooter. This is a frequent point of adjustment, and I'm wondering if that metal piece that when the ball is popped guides the ball to the shooter rod is mis-adjusted. When the ball does pop up, it should strike this metal extension and be guided to the lane back to the ball shooter rubber tip. When it's mis-adjusted it can prevent the ball from going into the lane, or allow the ball to pop up, hit the side rail, and drop right back into the ball popper area!