Similar to the bug described in this thread.
How to reproduce it:
Equip Pukestabber (with the Iron Stomach enchantment unlocked) Rest using alcohol -> there won't be any hangover penalty (which is the expected behaviour) Rest again using alcohol -> now there will be a hangover penalty (which as far as I understand is not supposed to happen)
Basically as long as one keeps resting using alcohol consecutively, every other time the character will get the hangover penalty.
I'm not sure if I should make a new thread for this. Anyway, the same bug happens if you have pukestabber equipped (with the Iron Stomach enchantment). Should prevent hangover, but every other time I rest using alcohol in a row, I get the penalty.