Pretty Crazy Kindred Exploit

There's a rare glitch that occurs under some specific circumstances that I cannot understand in which Kindred is allowed to mark the same exact champion again. I know for sure that I marked them, and about a minute later killed them, and I was then able to mark them again without a cooldown about half a minute later. This can be confirmed by my teammates, Nami and Caitlyn, that witnessed this in the game in which I went 13-5-1 as Kindred. I'm sure that the cooldown for the passive itself did not reset, only the part where I was able to mark the same person again. The mark did work as intended and I ended up going from 9 marks to 10 and then to 11 after killing the enemy Draven again. This has happened before but I haven't really noticed it until now.

Basically just inspect that Kindred game in which I went 13-5-1 and you'll notice that this does happen.