I don't think it's glitched, I think it's just hard and I have never understood why achievments can't be hard. The only ones I disagree with are the ones that there is no feasable way of completing purposefully such as "beat a developer in multiplayer".
That said, I still don't have this. I've spent over an hour killing myself over and over with the aimless suicidal jump. I can angle it right, I can get behind him, I'm turning off the sprint and I'm holding down to assasinate not tapping.
But if I keep on landing a few feet short of him HTF am I supposed to kill him?
Is there a trick to getting more distance from the jump? I've hit him a couple of times, but never got the achievement as I think I turned off my sprint too late so the fall wasn't fatal.
Any advice on getting a few feet extra on that jump would be greatly apprecaited.