I believe it is still possible to get it as an 85 from lower level dungeons, (no idea if blue has confirmed this as a bug or not) but if you were running your friend through, it could have worked sort of like a profession recipe dropping.
Since you already completed the quest (and it is bugged so you can't turn it in again this month atm), it only allowed your friend to roll on it since they actually needed it.
It might also not be dropping for people who have already completed it since it is a one-time quest item until Blizz fixes it, much like the tracking beacons to get the robot chicken.
Both interesting theories. Perhaps I'll take another 85 out and attempt to farm for artifacts. Of course it will take me several hours to be able to determine if I'm just seeing bad luck or if these drops behave the way I think they do.
It's also really difficult to figure out what is a bug and what is intended when it comes to these things dropping at this point. It would be really nice if a blue would come out and address the situation. But I'm not getting my hopes up on that happening.
Perhaps you're right in that I literally cannot make these items drop as my main because I've handed one in this month already. That would be phenomenally
stupid and destroy their concept of being able to farm the items during the rest of the month. But again, without confirmation it's impossible to say. This literally undermines the entire purpose of the drops since it means the people who are trying to farm them are rendered unable to farm them. Then the AH prices go up due to rarity. And everyone loses
This is some of the worst execution I've seen in a long, long time.
(Cross-post from the Achievement forums. Probably won't help. But I'm looking for any insight from the blues or other players in how exactly these drops are working now)