Forerunner Gaming

So I got a quest for killing 2 people while falling with headshots with a deagle or a rifle, I've killed around 5 people while falling with either a deagle or a rifle with headshots, with their heads exploding. None of these times did the quest even go up 1 of the 2 ticks, and it's making me rather annoyed considering how it wont let me abandon the quest either. I don't know how to fix this but it's rather annoying as I've well over completed the requirements, and even did so in a round just now and it still didn't work. If someone could get back to me on this or something that'd be great.

I don't do that quest because I feel like it should be a hard quest, but I feel like you have to do this by falling off a building and shooting someone in the head or something like that.

Were there enough people on the server at the time? Quests wont count if the player-count is too low.

There were at least 11 people on when I had done this yesterday, I believe that is above the required amount.

I'm pretty sure if you jump off it doesn't count.

You have the walk off the ledge.

I feel you should be able to jump, its an easy quest, and that makes it into a VERY difficult one.