Quinn's vault ability cancels out Illaoi's q damage

I was playing a normals game as illaoi top lane against a Quinn and i noticed that if Quinn vaults on illaoi during her q animation, she doesn't take any damage and i'm not talking about before the animation is complete, even if the tentacle slams down on quinn, as long she vaults, she won't take damage. It really cost me some trades and i'm pretty sure that quinn should have taken damage from my Q. I hope riot fixes this soon because it makes a difficult lane even harder than it needs to be.