Illaoi v Quinn bug (?)

Situation: Top lane, solo, vs enemy Quinn

Bug(?): Any time Quinn uses her E Vault on Illaoi within the windup period of her Q Tentacle Smash the animation continues to go off yet no damage is dealt. i.e. I see the tentacle smash Quinn (and minions) in the face but nothing happens. I understand that Vault has a small knockback attached to it however Tentacles Smash is neither a channel nor has any cast time associated with it so even if it is intended it is VERY unclear and very confusing in the middle of a fight to see just no damage happening even when you have clearly hit your ability.