Steps to repro:

1. Open attached project and 't1' scene;
2. Notice that a cube has a blue'ish tint;
3. Open Lighting window (Window>Lighting>Settings);
4. In the Lighting window press on the cogwheel icon and click Reset;
5. Notice that cube has become white;
6. Save the scene;
7. Open scene 't2';
8. Open scene 't1'.

Expected result:
Cube is white.

Actual result:
Cube has a blue'ish tint meaning that reset Lighting settings were not saved. See attached video.

Notes:
- Reproducible in 2018.2.0a1, 2018.1.0b4, 2017.3.0p2, 2017.2.1p2 ;
- Reproducible on Windows 10.