Occasionally while doing certain tasks, mobs will visually freeze in place, but attack you as an invisible, invulnerable mob. The hitbox goes missing and you can't preform actions on special mobs (i.e riding a horse). If a friend is connected they can see the mob and kill it, but on the victims screen they are making the "strike the air" sound. The only way to fix this is to reconnect on the world, like how ghost blocks works. The only way I get it to work consistently is when I dismount a horse in the air.