Class Challenges keep changing

For starters, I came back to the game after about a week to see that the challenge values have changed dramatically, not to say it's a bad thing, but for the LMG I recall having to suppress 200 enemies with LMGs then it became 10, now I am seeing you don't have to do it at all, so what's the point of a CHALLENGE???? My main complaint is the class challenges are just a mess imo. The last support challenge is a buggy mess. I had completed the review 20 players in a match and now it changed to 50 in a match???? The damage with the fire launcher just doesnt count at all. I hit someone directly and killed them without any other sources of damage, only for it to track 1 point of damage instead of 100. This happens every time I deal damage with it it would only track 1-10. So is the challenge to deal any type of damage, and it counts as one? But I remember one instance where I hit someone and a mine, and it tracked it as 600 damage. So what is the challenge I am just confused and quite frustrated after playing for 2 hours and focusing on the fire launcher challenge to only make a dent because of a bug. Before that, using the grenade interception device wasn't counting either it would only count sometimes, even when I saw it destroy grenades. I just don't understand all the value adjustments yet the challenges themselves are buggy. FYI this is my first BF game. I was a COD player for years, and I genuinely like this game way more than the past couple of COD releases.