I think I have solved it but it's hard to test out, gonna have to wait to see if I or someone else spots it again once I push out the next build. There is a problem happening when an enemy avoids an attack which causes the animation system for enemies to crash. I removed avoidance entirely which I thought solved this but I think an enemy attacking itself and missing might count as avoidance in the fucked up rpgmaker logic. Raised hitrate on enemies from 95% to a 100, if the problem is what I think it is this will solve it and it explains why it happens so rarely. One in twenty chance if an enemy is confused. Your build will still have this issue at the moment however, and I cannot really be sure until a new build is out and has been tested a lot.