I do not know if this is a mistake or a deliberate action but it would be good if potions Purified Stimulating Scent http://www.rom-welten.de/database/view.php?id=200276 or Pungent Vileness http://www.rom-welten.de/database/view.php?id=506691 did not disappear after using the skill of the knight Threaten http://www.rom-welten.de/database/view.php?id=490153.
At the moment these potions for the knight are useless.