Cho'Gath Ult Bug

Hello, TanksBeDank here, rocking a solid 400 games of Cho'Gath so far this season. I've had an ult bug off and on , all season and I think I just hit the threshold of my patience for this Cho ult bug.

Here's what happens:

-I go to use** R [Feast]** to last hit a minion, but the minion dies to another minion before the ult finishes casting -My ult goes on cooldown--- DESPITE me not getting a stack or gold. -I ping (frustratedly) to my teammates that my ult is down -My ping reads "Cho'gath R- Ready" DESPITE BEING ON COOLDOWN

-Either reset the ult CDR on a missed cast in situations where the target dies during the cast animation or give me the ability to ping that I don't have ult in this situation- I'm tired of wasting precious stack time, and I'm even more tired of misleading my teammates with my pings.

This is not a bug that I experience every game, but I am experiencing it in about 10% of my games Yes I could just be feasting the minions before they lose so much HP, but sometimes a top lane tank wants to freeze a wave __