In the quest "Bee's in their Mouths" in Khrysalis at Fort Rachias, you can skip the boss battle between the 2 shadow weavers by exiting the arena where you fight them, and then if you fight 2 gloom dancers, it will act as if you fight the 2 bosses instead.
I found this out by thinking to myself "Hmm, I wonder if you can fight 2 gloom dancers as it says "Defeat 2 Shadow Weavers as the objective""
Not a huge game-breaking bug, but it can be seen as a exploit to bypass fighting these 2 bosses.