Maybe try setting the atmosphere via the "Edit level data" and then rendering all light probes and reloading the level. Make sure you have light probe of the "distant" type instead of "local".
I did all that indeed on the level where the screenshot was taken. I'm using a probe light as "distant" type that is giving this results. I've tried even using a new extra probe with local type (showed on one of the screenshots in the GoogleDrive's folder) and switching between the options Diffuse and specular/only diff/only spec while rendering each one of the "capture types" to see if the results would change.
And I'm always using "render all light probes" on the level menu instead of rendering individual probes.
