Cho gath R Bug

ive noticed recently a bug on 's Ultimate - When you use Feast on a unit - it can be champion monster or minion, and that unit dies during that tiny window of the Feast channel, the ability glitches out and goes on cooldown, without doing damage and without giving a feast stack I know many people dont play Anymore so maybe thats why Riot doesnt seem to want to fix it, but as a cho gath main its really annoying to have wasted your ult on something as stupid as that I can tell that this isnt intended either, because when i ping my ult icon, it tells me that its ready, although its clearly on cooldown. The green dot on my champion icon is present on my teammate's screens as well

https://vimeo.com/user102286702/review/356398736/563086f1e0

If you look at the video you can see that Cho has 8 stacks before ulting, he ults the kayn, doesnt get a stack, and it goes on cd. I also pinged my ult to show that it still is shown as ready.

This bug is really annoying and can sometimes even cause you to die or back off until its back up again. ive noticed other posts, some over a year old complaining about the same issue, so I dont know if what im writing here will amount to nothing, but hey at least i gotta try

edit: apparently on this specific replay it actually doesnt show the ultimate going on cooldown, which is weird since on the previous replay it did, but whatever. In-game it went on cooldown and thats what matters