50 level warlock quest bugged?

[Erja]

I'm trying to get the warlock only Sunken Temple quest given by Impsy in Felwood, I completed "Hot and Itchy", where you bring him the felcloth, but can't access the next quest in the chain. Is this quest not in game yet or is this a bug?

[Lighthammer]

It was added in 1.8, the 4 dragons patch. I thought it was complete-able but didn't reward anything.