Lauren was in the Valus Mountains, exploring today and once she got to the foot of the mountains, she lost her dwarven sword. How did that even happen?

Looks like she has to find a new weapon

Did she fight with something and get disarmed?

My character occasionally “looses” a weapon or two from her inventory if she is carrying a lot of odd junk like ingredients and empty soul gems. It happened just today when she took her companions two weapons to repair and they disappeared. After giving the companion a load of junk and soul gems, the two weapons reappeared in her inventory.

Oh, yes. That's an annoying bug, too, because the thing that's "missing" is always the thing you need.