[GAMEPLAY] Still get targeted under Vlad's W

I was playing as Vladimir with a Nautulus and a Varus on twisted treeline against a Veigar, Jinx, and a Fizz. Nearly everytime I would activate my pool, Veigars stun would catch me even though I'm supposed to be an untargetable entity. To my understanding, that shouldn't have happened.

Just have Vladimir try to pass out or in Veigar's stun ring and you'll see what I mean.