That's very strange because the log.txt you included reports no scenery loading.
Does it happen with X-plane default scenery, or is it a modified tile?
I suggest you run the installer to see if any file needs to be fixed.
If no luck, can you try and install a second clean copy of X-plane? With just the area of scenery where you see that. It's important to check if this is caused by X-plane or by third party addons or plugins.
Browse the forum because I remember a similar topic. The search engine on top of the page might help. Sorry I can't give more help for now. (I'm not part of Laminar Research)