To add to the list of what could happen, just ran across this kick-out problem on a pin(Ship Ahoy) I worked on for somebody.

Ball would take a few times and or slow to kick out. Upon inspection what had happened is, the separation in the chrome trim ring that is in the kick-out hole was lined up in line where the kicker arm rests....so what was happening was the kicker arm was sometimes getting 'stuck' in the separation(slot)in the chrome ring from the arm going back and not hitting the metal insert, and it was also wearing into the wood over time.

Just a heads up. I have never run into this before w/a kicker arm so maybe it will help somebody else.