I am having issues where terrain is one way when I pass through an area and it changes when I pass back by after using a portal. Specifically a trench I dug to keep draugr in a building goes from a simple moat 2m wide to being a gaping hole extending under the building letting the draugr out. If I fill in the area and leave it turns into a mountain of stone covering the front of the building and filling in my trench. If I dig it out and leave it changes from a moat to a gaping hole again letting my sausage mats run free killing the locals.