H.U.D. Cooldowns not displaying correctly.

I've been plagued by this bug consistently through the last 3 or 4 patches. It affects every game I play, and in every mode. The HUD shows my abilities to be off cooldown, though I'm not actually allowed to use them for another few seconds. It also seems to be percentage based... For example, summoner spells take a full 10 seconds to be usable after they seem to be ready. It doesn't affect things like wards as much, though it's still noticeable. This stupid bug has led to MANY deaths with me mashing the key for flash, or my ult. Any help would be appreciated.