Fix Irelia's stun

So every time I face an Irelia, this one major flaw always made me throw a tantrum or smash my keyboard. Her E, Equilibrium strike, slows champs that have lower health % than her but stuns when they have higher health %. But Irelia's stun seems to work every time even when she has higher health % than me. Is Irelia's 2200 hp higher than my Diana's 1920 hp? I don't know what Riot means by higher health % but 1920 isn't definitely higher than 2200. Please fix this issue Riot...