I just played a game as Tahm Kench, and sometimes when I used my W, Devour, sometimes it wouldn't let me reactivate the ability to spit out a monster. This didn't happen for lane minions, but it would occasionally happen when I would devour scuttle crab, or another small neutral monster.
This has happened to me on lane minions from time to time as well. As much as I love playing him Riot needs to disable him to work out bugs before allowing him to be played again.
Mid 2016, I can confirm this bug still exists. Here is a link to a more thorough description of the bug. http://apollo-web-na-prod-704019941.us-west-2.elb.amazonaws.com/en/c/bug-report/P5P5eGyH-tahm-kench-w-bug?show=new
Too bad too, since I love the champ. I was already not picking him as much bcuz of the inability to specifically devour enemy champs if u have a teammate standing on top of them (which can have drastic consequences in late game team fights).
