There is an issue with the quest. It's not necessarily bugged, however, you MUST be quick on the draw. On completion, you need to turn the quest in to Thrall before someone else talks to him and allows him to escape the cell.
Once Thrall has escaped the cell you will not be able to turn the quest in until the next time you're in the instance.
Edit: Why is this being rated down? This is definitely valuable information I wish I and my group had known before we got in there. One of our group had already been in here and completed his quest in a previous instance... he allowed Thrall to escape not realizing the rest of us who were new to the quest could never turn it in.
Quest
Taretha's Diversion
A World of Warcraft quest in Old Hillsbrad Foothills. Facts and objectives from the current retail game data.
The highest voted Wowhead comments for this page. They are community notes, not TheWoWDB comments.
You have to burn down the 5 cottages by clicking on a [object=182589] inside them. These cottages can be found in the lower part of Durnholde where those [npc=18598] are.
For those seeking QUEST HAND IN => It can be done only before Thrall exits its prison. If he gets out, you need to either let him die to reset him or hand in the quest on your next visit to the dungeon. To be clear => You CAN NOT hand in the quest after you finish the dungeon.
Quest facts
The client quest POI data records no map location for this quest, so no map is shown.
Check whether you have already completed this quest
in-game: /run print(C_QuestLog.IsQuestFlaggedCompleted(29598))
Description
It was Taretha who created the original diversion at Durnholde, allowing Thrall to escape. Now the Infinite have captured Taretha. The diversion will not happen without our involvement. You must use the incendiary devices that I give you and burn down the internment lodges.
Getting there
Inside the dungeon: Old Hillsbrad Foothills
Deep within the Caverns of Time, the brooding dragon Nozdormu has awakened. Since the world was young, the bronze dragonflight has safeguarded the winding labyrinth, monitoring the shifting timeways to ensure that the delicate balance of time is upheld.
Bosses in the Adventure Guide, in order: Lieutenant Drake, Captain Skarloc, Epoch Hunter.
Entrance: Tanaris at 55.3, 53.1.
Instance text, bosses and entrances are the client’s Adventure Guide data.
Community notes from Wowhead · 26 comments
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Reward details
Reputation: Keepers of Time +1,000
The Keepers of Time are bronze dragons hand-picked by Nozdormu to watch over the Caverns of Time.
Reputation group: The Burning Crusade.
Other quests in Old Hillsbrad Foothills that reward Keepers of Time reputation: The Caverns of Time (+250), To The Master's Lair (+10), Old Hillsbrad (+10), WANTED: The Epoch Hunter's Head (+350), Escape from Durnholde (+1,000).
Item facts are the current retail client’s (ItemSparse); the specialisations for a pick-one item are the ones the Blizzard quest API lists; faction and currency text is the client’s own. Lowest listed price = the US commodity auction house now.