[GAMEPLAY] Issue Regarding Ability Cooldown Icons

https://imgur.com/a/unPgh I was playing as Aurelion Sol and the icon for his ultimate didn't have the cooldown timer on it so I assumed that it was ready, but it wasn't. The icon was clear as if it was off cooldown, yet as evident in the chatlog of the game it said that there was 21 sec left on the cooldown. This has only happened to me once before, but I forgot which champion I was playing it. Since it doesn't happen too often, I dismissed the problem as benign.