Veigar not ulting but using full mana bar.

I have had a few games within the last few days where I have built yordles and given my Veigar items like Guinsoos and Shojin, but although he autos and has Shojin mana regeneration on attacks, he just doesn't ult. No animations either. Just keeps attacking, mana resetting. Not sure if it has to do with enemies having Statikk Shiv but they have been on enemy teams when this bug has occurred.

I think the last game I had this happen it happened in 3 or 4 rounds throughout the game. Cost me some easy round wins which was frustrating.