Quoted from Whysnow:
looks to me like the 3rd ball it not fully in position over the upkicker before it fires?
hard to see but appear that it is not hitting square on the ball so it is rattling before it even makes it to the top.
I would take off the rough and check that there is not a burr or something stopping the ball from getting into position first.
It happens when starting a game with a full trough sometimes, too. That said, it's worth checking.
I dropped the coil strength down to 20 and it kicked a dozen balls in a row (in coil test) perfectly. Then in game play, it started failing like 20% of the time again. bumped it to 23 because it seemed a little weak (sometimes barely making the shooter lane), but it still fails at about the same rate. I'm going to have to take the apron off and try to get a better view.