Vi Bug

I just played Vi and I noticed two bugs with her ult. First of all I pressed ult as I died, but then my ult did not go on cooldown on my screen, yet my teammates told me it showed them that it was on cooldown. Secondly I ulted an Ashe, and while ulting I was hit by Ashe's ultimate and Vi completely froze. My ult did not complete, I stopped moving, and was unable to cast any other abilities for a few seconds.