Hi RushIsland,
This is a bug with the atmospheric rendering and I'm working on getting a fix out asap. In the meantime you can go to the "Tenkoku DynamicSky-->SkySphere-->fogSphere" object and disable it's renderer component.
Also you may also want to disable the built-in Unity fog, as Tenkoku doesn't currently handle color modulation for it.
All temporary, I should have these things working better together soon!