GAMEPLAY - Vi Ult bug - When I ulted a Kata my ult did not go off, however I just flew around

After i flew around following her, not being able to AA and do anything, I came back and did the knock up of my ult on no one but did the animation of the ult. I did not get a chance to record it or get a screenshot and this has only happened once in my many Vi games. Could have been a combo of Kata e'ing away and trundle pillar maybe glitching my ult