[GAMEPLAY] Irlea stuns you either way

so I was plying with a friend of mine and we were doing a 1v1, she was irleia and I was yasuo. When she was using her equilibrium strike on me at max hp (she still has more health than me by the way) she stunned me and proceeded to kill me. Was her stun supposed to go off when you have max hp or was it supposed to go off when she has less hp than you?