When it comes to doing this quest, you have to click on a crate, defeat the harpies, then move onto the next crate.
However, I ran into something tonight where this person before me opened up all the crates at once spawning 9 harpies at the same time if not more. Then they come in waves after that. Guy died, but the harpies were still there. They didn’t despawn, so this leaves the next person who’s doing the quest to clear those harpies in order to complete the quest.
I did this on my shaman main with a 5 man group including 2 healers when Classic was released. When someone in the group opened all the crates, we almost didn’t make it out alive, even with 2 healers and 3 DPS. So imagine that for one person.
If someone fails at it, could we get the harpies to despawn, instead of staying up?
I came down to the cave on my shaman to clear up the harpies, and I noticed if someone wipes during the encounter, the harpies not only stay up, but the encounter is stuck at whatever wave the person wipes on. My shaman cleared the first set of harpies which were still up. This caused the rest of the harpies and the named harpy Grenka to show up. So the event doesn’t reset either if someone wipes on it.