Azir's Ult does not always show time remaining

During an Aram game today in which i played Azir there was an instant after i had ulted (an ult that did in fact go off, doing damage and pushing enemies away) that my ult did not go "on cd." I asked my team mates if the circle next to my name was still green. It was. I tried to recast the Ult during the next fight and it would not cast, surely because it was actually still on CD.

This did not happen again during the game, but it did happen in an ARAM before, which is why i've decided to post about it now.

On my team: ziggs, karma, liss, cho and myself as Azir

Other team: Akali, Corki, Xerath, Garen, and Rammus

If i recall correctly it happened after i had Sorc shoes, the unholy grail and my nashors, but before the void staff and death cap.

To restate, I used my ult and it went on CD as it should, but it did not show my team mates that i had used it or did it gives any user feedback through the UI to say that it was on CD until after its next use which was several minutes later (after 2 deaths).