Hello.
I have 3 shots here which will illustrate my problem.
(Unfortunately I do not have permission to post links...how convenient.)

I have a big blackreach style cave system, though not quite as large. But for some reason, about half of my cave is moved a great distance ingame. Some walls and mountain props are not where they should be as they appear in the editor. Instead of seeing the far wall, I instead see the skybox.

Why are those static props being moved? Are there any common issues I can look into?
Thanks for any help.

There is a limit to how far you can go with an "interior" cell. If you go out of bounds, the pieces usually are moved to 0,0.

make sure the center of your cell is around 0,0,0. That might help. Or convert it to an exterior cell.

And I do believe Blackreach is an exterior cell, thats inside.

Thank you so much.