Oops.
Before you did this, did you try adjusting the advancement prawls on the bottom?
My shellplates had a little "snap" in them and sometimes didn't advance that last 1/16" which meant the primer wasn't always perfectly lined up on the backstroke and the sizing die wasn't always perfectly lined up when I pulled the handle down. After a bit of troubleshooting, I tried adjusting the prawls a little at a time, then returning them to their original position. I found that just a small twist on one prawl eliminated that "jump" or lack of advancement. The plate moved to each station in a completely controlled smooth motion.
I don't think there should be any jump in the LnL AP advancement at all. You should be able to move the handle as slow as you wish and the shellplate should be under complete control at all times.
I'm running into a similar situation where the shellplate will not advance that final 1/16" of an inch but the funny part is that it doesn't happen every time.... I can run several shells through that line up perfectly then it will act up for a few rounds.
I noticed that the spring that goes around the shellplate seems to have some kinks in it..... could this be an indication of something gone south or could this be the reason things have gone south?