This is a great plugin that serves my purposes, though I seem to have discovered a bug. It triggers whenever I use my substitute skill (which is set to only last 1 turn, with Remove at Battle End and Remove by Restriction checked on its substitute state) on a target that has a state with a restriction (Attack anyone, Cannot move, etc.) The user of the skill will continue to substitute for the target on following turns, and even in following battles, as long the user is still able to freely act, without me selecting the substitute skill again. But if I use the substitute skill on the same target again when they don't have a state with a restriction, then the user stops substituting for the target when the turn ends and everything goes back to normal.
I am using RPG Maker MZ, and I tested this with all other plugins off.