Jawa trade

I managed to solo a 4man hc quest a while back, by that I mean I killed the monsters and so on, but I didn't recieve the quest items, which I thought strange since I'd done the quest with another char and almost every item dropped on the first try. So I got a group for the quest and then the items dropped right away. So do you have to be in a group to recieve the quest items for a 4 man quest?