Im having the same problem, Im on blackfangs dungeon and have been rolling with 4 chars up to this point (Cleric, Monk, Warrior and Rogue). On blackfangs dungeon, it loads up the 6 player variant (i.e 8 locations instead of 6) and duplicates my monk and cleric (i.e when Im assigning chars, i have 2 clerics and monks to assign) .
It has also duplicated all of my characters 4 times, same scenario (16 characters total on the board) but after i restarted the game, we are down to ^^^^.