Bug for the Updated Engineer 3 Challenge

So I've been trying to master all four of the different classes and doing all six challenges. I've already completed assault and support and was doing engineer. Engineer challenge one and two were easy but when I did challenge 3, it wasn't working. All it says is to deal 2,500 damage to aircraft with launchers as engineer. It sounds simple but after 4 matches and and destroying about 3-5 aircraft per match, it still showed 0 damage done. I got some of my friends to paint it with the laser designator for me and tried that, but it still didn't work. I used all launchers available to me, that being the slm-93a and the mas 148. RPG-7v2 doesn't work and when I used the mbt-law, it randomly gave me 20 damage out of the 2,500 and later randomly another 420. It's been a week and I'm still at 440 damage out of 2,500. I'm assuming this is a bug for now until the devs fix it. Does anyone know of a way to get past the challenge engineer 3 until it's fixed?