[GAMEPLAY] - Tahm Kench's Q Stun and W Delay/Range

I played two games yesterday as Tahm Kench support and while playing I noticed that after applying 3 stacks of his passive and Q'ing the enemy champion, it wouldn't apply the 1.5 second stun. I constantly tried this in both games and noticed it never worked once. I would 1v1 one of them and as I saw an ally coming to help, I would attempt to stun the enemy with my Q. My Q would go off, apply its slow and damage, but never the actual stun that is stated in the description. Not too sure if anyone else is having the same problem. I've also noticed something slightly off with his Devour ability when it comes to allied champions. There does seem to be a delay to it. Either that or the actual range for Devouring allied champions seems to have a smaller range than using it on minions or enemy champions. Any insight to the problem would be appreciated!