it annoyed me quite a bit too. wasted tons of time getting the grenade launcher kill thing until i noticed that you could just use energy weapons that are grenade launchers. or that is what i thought, until the quest step stopped counting at 6 and didnt update at all. stayed up til something like 5am because i just wanted to finish this already but since nothing happend i decided to take a rest, apparently energy weapon grenade launchers dont count. log in the other day, all of a sudden i get random iron banner gear gewards after accepting black forge bounties. so for whatever reason the game only updated after i accepted another bounty... that was such a pointless chain of using random weapons.