Wind Wall

First off, I'm not sure if this would be considered a bug, and I feel like most everyone knows it's in the game, but I just want to clarify.

When Annie has her stun ready for her next spell cast, if you block the incoming spell with Yasuo's Wind Wall it blocks the spell, but Annie still has her stun ready for her next spell even if it's blocked. No matter how many of her spells you block she still has her stun for her next spell. I feel like this is a little broken only because it takes nothing for Annie to be able to spam 4 spells and build her stun up again. Considering she never runs out of mana spamming her Q for last hits while building up her stun.

If this is supposed to be the way it is, then I suppose this thread should be in the Balancing department. Either way I feel this should be looked at and determined whether or not Yasuo's Wind Wall should get rid of Annie's passive if he blocks her spell.