Ultimate Bug

I was playing a game today with 5 friends in a normal game with our support being a malzahar. He used his ultimate on a nocturne which im not sure if it went through or not because of nocturne's spellshield. However for everyone else in the game but my friend (LMJeffJones) playing malzahar, the ultimate bubble was still a solid green meaning he had ult when he already used it. We were in the same room as well so he turned his computer towards me to prove that he wasnt lying and indeed his ult was used and on cooldown.