Darius & Vayne Bug

So I found out this small bug that can trigger between a Vayne and a Darius. It may be considered small but if you are a Darius and there is a Vayne in the enemy team, this can be a crucial factor in who wins the fight.

If Vayne activates her ultimate and tumbles in the same moment as Darius is performing his ultimate, the ult won't do any damage at all (I think it adds Bleed stacks though) and from what the Darius player told me, it'll go on CD (I was the Vayne when it happened).

I'm not sure if it can happen to anyone or if it just happened to me, but here it is. You can try in a custom game I suppose.