A little late to this, but I have been having the same problem recently. I think a big thing for me is my headspace when I do PTs, but also when I just do drills. I can imagine that even if you think your publication isn't having much of an effect on you, it may actually be. I find that before I study or do PTs, I really need to just clear my head and relax. I try to either go for a walk or sit on the couch for 10 minutes and do nothing. Stress and anxiety, I find, play a massive role in how I do, and managing them almost always results in me doing better. If I had any advice, it's just to relax (I know this is much easier said than done), you are already scoring high on the test, and it's clear you know the stuff well, just remember that at the end of the day it's just a test, try to clear your head before you do your LSAT stuff and just trust what you know.