Warwick's ult doesn't work on Yasuo

Across two different ranked games I ulted a Yasuo a total of 3 times. Each time, my ult didn't suppress him, and I forget if it did damage or not. I'm too lazy to test it in a custom to find if there's certain steps that need to be met beyond him being Yasuo.

However, I'm a D1 Warwick one trick, and several other people commented on it really confused as to what happened. He DID NOT interrupt my ult with his torando, and he was all alone, so no other champ interrupted it. He also did not have QSS.

If someone can test this in a custom that would be appreciated. I have a theory that the bug might result from Yasuo having a full wind bar thing.