Other mistake: The description of Alastor's Hood states that it can be used to Haunt a foe, however when used, it will attempt to Condemn a foe for an instant kill instead.
Plot hole: Even if you've acquired Piers's ship before visiting Garoh (a city populated by werewolves), when you first set sail in Piers's ship, Sheba will say, "We've already met werewolves."