I know it’s not there in vanilla, but it makes the game totally unplayable for group, which is quite the opposite of the spirit. Shared quest item (everyone can loot the same quest item) encourage people to play together instead of solo.
Posted from the Council — voting happens there; discuss here.
It hasn’t happened here on Stonetavern (for me) yet, but on other vanilla servers I’ve run on have not had this issue … so I’d be surprised if it’s a problem here.
Run Deadmines.
Need VanCleef’s Head for the quest.
Kill VanCleef.
Loot 5 VanCleef’s Heads (1 for each party member).
That’s been my typical experience on other servers. Is that not the case here? 
There are, of course, exceptions … such as needing Twilight Pendant x10 for the Twilight Falls quest (Alliance side), but there only being 30 Twilight mobs who drop it per instance … in an all Alliance party only 3 of the 5 can complete the quest per BFD run (and the remaining 2 need to rerun the dungeon to complete the quest).
There are some open world mobs that need to be killed farmed for their quest drop item(s), so you’ll wind up with Wash, Rinse, Repeat until everyone in the group can get their quest loot. That isn’t always a bug, sometimes it’s a feature. 
The “bug” is when people “get theirs” and immediately ditch the group 
rather than staying to help everyone. 