Sion ult bug?

yeah that's a bug LOL

So here what happened. As u slow the clip u see that the amumu hit his q on the sion. Now the time that he hit his q is critical u can see he hit it just as the sion ult would have hit him. So what I'm thinking happened here is his q went off and was registered before the sion ult registered so he was already behind sions hit box by the time it got to him.