Garen Ultimate Bug!

Garen's villan component to his ult doesn't switch quickly, or at least doesn't seem to switch to the proper enemy. From what I understand, the Villan passive part is that the last enemy to kill someone other than Garen is the villan, and will be marked as such for a duration of time unless another enemy gets and another kill. I play many Garen games, and I have noticed that the villan passive doesn't switch as often as its supposed to from my understanding of the ultimate. There have been games where someone has 6-8 kills and never once ends up being the Villan for me as Garen, and no its not the enemy top laner slaughtering me in lane for 6-8 kills because Garen is a terrible champion, with very limited mobility, with next to zero CC, who gets slaughtered by everyone in this meta and not really scaling to make him relevant! But yea, I'm not bitter or anything that his champ sucks and I play him! :D