Illaoi "E" does not work on garen?

I was just in a game playing against a Garen, and whenever I used my "E" I would kill the spirit but it did not activate on him. this happened every time I killed his soul.

i'm not sure if it was a bug, or hack, or just some sort of passive that garen now has. I've played against that champ before, but i don't remember him always breaking free from the kraken instantly after successfully using the "e" ability.