I posted a this problem once before and never did get an answer to it. I thought I had fixed it by removing her from Fossilyum in SSEEdit when I started a new game.
After LOTD updated I installed the updated LOTD and had to reinstall all the patches for it. I played the game until I got to the fossil camp and I saw two Darnette Lauven, I realized I had forgotten to remove her from Fossilyum so I did so and went back to a save I had made after exiting Northwind Iron Mine, thinking that was not in the fossil camp cell. Unfortunately my game would not load. No matter how far I went back on my saves my game would not load after removing Darnette Lauven from Fossilyum.
I have just kept playing with two Darnette Lauven as it does not affect my game in any way as far as I can tell. They are both listed as essential so they are both going to be wandering around wherever the game tells them they can go.
I would still like to get rid of one of them, preferably the Fossilyum one, if anyone knows of a way to do that.
Never mind, I am an idiot. I just went to the Fossil Mining mod in Nexus to post there only to see that Fossil Mining should not be installed with the updated LOTD as i is integrated with it.