[Gameplay] Cho's ult not showing cooldown

I ulted a gragas (with autocast on) right as I died. The ult went off and damage was dealt, but the cooldown was not shown. It looked as if I had the ult ready to use, but it did not work until (I presume) the cooldown was off. This only happened this one time during the game. Apologies, for I have not tried to replicate this bug.