To reproduce:

1. Open the project, attached by the user (MSELightingBug.zip)
2. Open "active" scene
3. In the Lighting settings, observe the following:
the Skybox is "skybox", the Sun Source is "directional light", Indirect Resolution is 0.02, Lightmap Resolution is 0.02, Fog is active
4. Open "game" scene
5. Step 3
6. Open "active" scene additively
7. Step 3. Observe how some settings are from "active" scene and some are from "game"

Expected: Lighting settings show the settings that belong to the currently active scene

Reproduced in 2017.1.3p3, 2017.2.2p3, 2017.3.2f1, 2017.4.1f1, 2018.1.0f1, 2018.2.0a8