Feign Death aggro question

Haven't played hunter for a week ...
And today in instances, I found that my Feign Death isn't dropping any aggro at all
I don't remember reading any changes from patch notes...
Is this a bug or is it hotfixed?

Thanks
If you feign then pop up immediately, aggro might not drop.

What were you trying to feign off?
City guards will NOT de-aggro.
Mostly trash mobs in 5 man instances
Sometimes I pull aggro coz I aoe too much so I feign death then continuous my rotations
Never knew that it might not drop if I get out of it immediately thou...
I'll try it again later
Thanks =)
ya it definitely fails if you dont play dead for at least a full second, even with my 60ms.
I wait for my character to hit the ground before I cancel out of it. Too many times I've canceled too soon and it didn't trigger the aggro wipe.