Okay, I think I fixed it. The bug is hillarious, actually.
It's supposed to set a flag called "HAS_WHISKY" when you buy it. But if you succeed in the Charisma check, it sets a flag called "HAS_WHISKEY" instead. Or as Katie would say, "some of that weird foreign shit". Fixing.
I'll try to do a new set of builds today; I'm in the middle of writing content for Act II, so I need to fence that off so it doesn't escape into the wild.