Happened to me a couple of times, when different quest mobs are within the same area.Well in this case it had been at the same spot for 15 minutes after the quest was done. None of the mobs were looted - as soon as a target was dead it went on to the next one. There were dead, lootable mobs all over the place and they kept respawning (low level area, almost instant spawn).
In this case the quest was already done though and it never got to delivering the quest. I closed HB and reopened and at this point it had been killing mobs for so long that the profile would move on to the next quest hub without turning it in (because I was too high level for this now).Happened to me a couple of times, when different quest mobs are within the same area.
Would kill a mob that has a quest item, not loot it and fend off the agro/nearby mobs while searching for another item drop OR waiting for an item drop that starts a quest.
Most of the issues i had while leveling were solved by stop/starting HB or clearing the cache if that doesn't help!