1. Open Unity;
2. Create new project;
3. Add some simple gameobjects (plane, cube) to the scene;
4. Observe directional light intensity with default values in 5.6;
5. Compare the values with the same project created in 5.5.

Actual result:
Rendered Ambient intensity value differs from 5.5: it's significantly lower and the default color of reflected directional light is more yellowish comparing to 5.5 (see attached screenshot). Note that both Directional Light and Lighting Inspector values are identical
Regression introduced in Unity 5.6.0a3.

Expected result:
Default rendered light intensity values should be the same in 5.5 and 5.6.

Workaround is either to restart Editor or to build project to Standalone.

Notes:
- The underlying reason for this bug might be Ambient Intensity value that could not be adjusted in 5.6;
- Reproducible in 5.6.0a5, 5.6.0a4, 5.6.0a3;
- Not reproducible in 5.6.0a2, 5.5.0f3;
- Reproducible on Windows 10 and OSX 10.12.1;
- Reproducible only in the new project;
- The issue is happening only in Editor and doesn't happen in Standalone builds.