[GAMEPLAY] Cho'Gath Feast Cooldown Doesn't Half Itself

This is a glitch that happens to me alot when I'm jungling with Cho'Gath, and I find it to be pesky. It hasn't ever happened when I use it on minions, or solo beasts (Dragon, Baron, Toad). I think it has to do with Cho'Gath getting hit when he feasts.

1. Fight a jungling creature (I find it to happen mostly with the bird creature thing)
2. When the Large Creature is below 1000 health (click on them an look at top let corner) use Feast on them
3. Try to get hurt the same moment you feast

Here is a video of it happening. As you can see, the beast has below 1000 HP, and I gain a stack of Feast, yet I still have an 80 second cooldown.