I can't seem to get it either, I wonder if it's because you still have a lot of other stuff to do? maybe there are hidden requirements , there is a lot of grey in your scenes gallery, you haven't done any of the Drugged sex or Jenny's blackmail scenes, which seem like a stepping stone to drunk sex... I know they are a few changes after you start dating Jenny, the Drunk scenes might be trapped behind those?
Edit: I did Jennies quests and all the others that seemed to make sense but the scene still isn't triggering... guessing you borked something when you tried using URM on it, I'm all out of ideas.