In the mod I'm developing, the armor has a special attribute; it disappears with the player when the player uses an invisibility potion. It works well, but since the armor disappearance is only visual (it just sets the armor skin texture to an empty .png), mobs can still track the player normally. I already have a tick handler set up for my other armor effects, so it's just a matter of removing the player from mob trackers after a potion check. How would I go about doing this?

It looks like you'll have to edit base classes. I'd say you put an extra condition in Chunk.getEntitiesOfTypeWithinAAAB.