I'm seeing something very similar on that same level, however the problem is much worse for me. It seems that all my characters have had their equipments swapped around e.g. my Hero characters have equipped a Power Orb, the big lizard man has a full set of equipped steel armour. Several characters have weapons they normally couldn't use equipped (e.g. one of the lissit has a bow). I also notice that NONE of the lissit ( except for the one right at the north of the map) had a mace of any description. The only one I have on me is a rusty mace I picked up in the tombs. It seems the NPC merchant character has also aquired some of my team's equipment; I doubt he was supposed to have any metal equipment, nor an equipped lance.
I have seen this happen before, where characters seemed to swap equipments on game reloads, but I can't honestly say exactly what causes it. I think I hit some form of item duplication glitch early on in the campaign (a couple of weeks ago, I think I saw it was fixed in one of the patches) which might have screwed things up.
Is there a way to restore the proper equipment of the lissit, and reset who is supposed to have what?