Tahm kench can't eat lucian [gameplay]

It's been a while since i haven't played TK in a normal game. So as I earned a discount on URF Kench, I decided to play him as support. I had lucian with project skin as an adc with me. In lane, we were facing lux and zyra (quite bizare but anw). So whenever i tried to eat lucian with my W, LITERALLY SPAMMING MY W ON HIS FACE (seeing that it wasn't working), i faced the same thing : just like when you wanna troll a guy and interrupt his back by eating him, it prevents you from doing so and your spell isn't cast. I checked my bindings : nothing wrong ; I checked if eating my mates was working : it did work ; i checked if eating minions or ennemy (with the three stacks) was working : it did work So, as it was a painful 50 min game with no way for me to help my adc at all, i'm begging you to start looking forward to fixing it. Thx Rito