Originally posted by jonnin:

Then there is a bug where they lose track of you and are vulnerable to BS even after having attacked you or been attacked by you. Which is not really game breaking, since only a few things meander mid combat and most of them are in the forest or meadows

Backstab can only be applied to a given target once every 300 seconds (5 minutes), even if you break combat and they go back to unaware/searching. That's the only thing that prevents them from taking the bonus damage if they're not aware of you. If you are really patient and don't get bored easily you can just continuously backstab and then break combat and wait until you can backstab again.