Edit: best guess is that I was being derpy with the new interface. Please disregard
v0.5.6a, Windows 7
I'm having some odd potion behavior. I purchased a few potions to my backpack (beauty and hair dye), and used them on slaves I then traded/sold. A few days later, when I checked my backpack, they were still there. Not sure if they weren't properly used up in the first place (though they did disappear from the interface upon use), or if they were somehow refunded when I sold the slave. I'll try to test this further.