I started the "Hunting The Garrote" quest and upon accepting the quest a new quest location appear, "garrote tracks" or something like that.  The bug occurred after moving my hero to this location to complete the next step in the quest.  As expected an option menu appeared with the standard "continue or give up" option.  Selecting the "continue" option started a battle (as expected) and the "give up" option exits the menu and the quest end (I assume this is expected, would be nice if it wasn't). 

The bug comes in when at the option menu, I press the ESC key on my keyboard.  The menu closes and the quest location disappears.  When I moved my hero to the former quest location, the game initiates an auto-save just as if I had selected the "continue" option.  By reloading my last auto-save I was able to engage in the battle and continue on with the quest, even though it would appear as though I had cancelled the quest. 

I have not yet tried to reproduce the above scenario by choosing the "give up" option, so this may be a bug from abandoning a quest rather then hitting the ESC key. 

On a side note.  I would love for there to be a non-bugged way of choosing the "give up" option and still be able to come back to the quest after a couple of turns rather then just abandon the quest all together.