The Skylands files are corrupted. Many chunks (mostly the empty though) are damaged and one cannot build there. I am currently evaluating what to do to fix it. At the minimum we will get a rollback. In the worst case scenario I will block building there and simply copy-paste one build after the other into a new world – however that will look like. The 200×200 lots are too big to reset so there might be some alternative in the works.
Currently the skylands are disabled, I will re-enable them once I know how to handle that.