This is one of the Shadow Pan dailies in Townlong Steppes. The quest involves collecting Highly Explosive Yaungol Oil Barrels from Fire Camp Gai-Cho and then getting on your flying mount and dropping them over mantid or yaungol in the Gai-Cho Battlefield, to kill 100 mobs.
The bug is that:
1. Nothing prevents players from dropping the barrels over Fire Camp Gai-Cho itself, where other players are either collecting barrels, or killing 16 yaungol for the other daily "Assault Fire Camp Gai-Cho".
2. These fire barrels kill players of the opposite faction as well as mobs. Each barrel does about 250,000 damage, so it's a 2 hit kill, or 1 hit if you're low on HP fighting mobs.
This ensures that there is continuous griefing on PvP servers. Today, on my server, a bunch of Alliance were doing nothing but flying overhead over Fire Camp Gai-Cho and dropping barrels of oil over Horde who were questing there. Since each barrel is pretty much a one-hit kill, it was impossible to quest there. Alliance could do this at no risk to themselves, since they were dropping barrels while flying high overhead where they could not be targeted from the ground.
Eventually, the Horde got tired and Horde players began doing the same thing. This put an end to all questing there, since everyone was just flying overhead, bombing anyone who tried to complete his 2 daily quests in that area.
I know that in the past Blizzard has discouraged such exploitation of game mechanics. Way back a few years ago people did something similar in Gadgetzan, climbing on top of buildings where guards couldn't reach them and shooting at enemy players below. Blizzard put a stop to that eventually by giving the guards ranged weapons instead of melee, so guards could attack players on the roof tops.
So my question is whether this current exploitation of game mechanics in Fire Camp Gai-Cho is something Blizzard overlooked and plans to correct, or whether it's "working as intended".