Challenges.

It took me a long time too. Most times it didn't count. I don't know why. Maybe the enemy heard the incoming sound and was clearing the laser designator right before impact?  I just kept at it and eventually got it.

I blew up a tank with my AA launcher and my brother in my squad as a recon and I’m still sitting at 0/1000. I’d be less irritated if I was making progress at least. 

You have to use the launcher for aircraft.....on the vehicles. That is very confusing. Even then It doesn't count most of the time. I blew up a tank and hit several others, it only counted 2 times. Been playing 8 hours now trying to do this. I give up. Just now I tried to continue the challenge for support doing damage with the incendiary gun. Set 5 players on fire, no progress. A very frustrating gaming day. I regret buying this game. It has some fun moments but also a lot of frustration.

Both my buddy and I completed this in two games. One go recon with the laser designator, the other with the laser lock on missile (MAS 148 Glaive).

One paints, both aircraft and ground vehicles work, the other fires.

It's not hard at all. 

There is an issue with tracking but also i think a lot of times it doesn't count is because the tracking dart which also paints targets isn't deemed as a laser designated.

Like for recon there's a challenge to laser designate 'x' amount of targets, it wont count for the dart paints, since the challenge is specifically "laser" designated it becomes an issue. There's no way for engies to tell the difference between dart vs laser paint it feels like there's no progress.