Quest: Black Label
 

During the course of this quest, I let Ben Gorefiend go, and now the quest text says "Tell Torfin about Ben Gorefiend's escape".
I went back to Torfin and told him of Ben's escape but the quest goes nowhere. I can keep telling Torfin that Ben escaped forever, actually. The option never disappears and the quest doesn't update.
Is this a bug(in which case I'll report), or I'm missing something here?
Your feedback is important, so I can confirm or not the quest is bugged.

Thanks!

Same thing happened to me.

Known bug. From the bug thread:

Quests and Bosses
Black Label: If you let Ben Gorefiend go instead of killing him, the quest becomes stuck. You can tell Torfin that you let Ben go but nothing happens afterwards.