Dun Morogh - Bitter Rival quest not completable

Current behaviour:

During the Quest "Bitter Rivals" your supposed to replace the "Guarded Thunder Ale Barrel" with another Barrel. What doesn't work tho is after you clicked on the "Guarded Thunder Ale Barrel" and read the text, Jarven Thunderbrew is supposed to have the quest "Distracting Jarvan" this wasn't the case.

I had to add myself the quest with a command, to progress further. The rest of the quest worked perfectly, aswell as the scripting when completing the quest "Distracting Jarvan" and when you replace the barrel.

Proofs for expected behaviour:

Comment on wowhead - http://www.wowhead.com/quest=310/bitter-rivals#comments

1. Once you reach the basement, check out the barrel beside Jarven Thunderbrew. You'll get a message that it's guarded.

2. Talk to Jarven Thunderbrew (he now has blue ? above him). You'll get this quest: Distracting Jarven

3. Once you get Jarven out of the way (by handing him the Thunder Ale from the Innkeeper upstairs), click the barrel again.

Include the ID for the game objects, npcs (creatures,pets,minions), spells, items, quests, instances, zones, achievements, skills:

Quest "Bitter Rivals" - 310

Quest "Distracting Jarven" - 308

Guarded Thunder Ale Barrel - 269

Jarven Thunderbrew - 1373