This skill simply will not fire. It has now happened in multiple locations/dungeons/trials.
The issue is not distance or line of sight. The keypress even regsiters on the bar (with the icon showing the keypress animation) but the skill won't fire.
While switching to another taunt (which fires without issue - Leashing Throw, Inner Fire, Explosive Charge) does taunt the mob, it not only means a loss of nearly ~9,000 penetration, but also then having to compensate on the fly when a skill that should fire does not.
This is simply not playable in difficult content. It's causing group deaths, due to taunt loss, and a huge drop in DPS, due to the penetration loss. Players should select skills for fights based on the mechanics, not on whether a skill will actually fire.
"I can't taunt" - a phrase I have said way too many times lately. This is a core tanking skill, it NEEDS to work. This isn't like other reports of skills taking 2, 3, or 4 key presses but the skill itself just simply stops working on some mobs and bosses no matter how many times the key is pressed.
While this is obsviously a bug, a serious one at that, I'm posting this in General as a way to highlight the problem and to let others know - Do NOT trust this skill to work. I have seen multiple reports from players about skills not working, I am yet to see anything from ZOS. Whatever changes you've made recently have broken a core mechanic - you need to show some respect to your players and comment on it.