Steps to repro:

1. Open Unity;
2. Open attached 'LitObjectsTerrainUnity.unitypackage' package;
3. Open 'test.unity' scene;
4. Set the camera angle in such way that you could see terrain with green bushes;
5. Select Directional light gameobject;
6. Increase light intensity to 8 by dragging scalebar;
7. In the scene view hold right mouse button click and change the view angle a bit;

8. Notice that bushes on the terrain are lit from within;
9. Set Directional light intensity to 0.

Actual result:
The bushes are still lit, though light intensity is 0. See attached gif video and actual.png screenshot.

Expected result:
The bushes should not be lit from within when directional light intensity is 0.

Workaround is to press right mouse button and change viewpoint angle in Scene View.

Notes:
- Reproducible in: 5.4.0b5, 5.4.0b4, 5.3.2f1 and 5.3.1f1;
- Reproducible in OSX 10.11.3;
- May reproduce in Game view sometimes (especially when using first person controller);
- Reproduces for both realtime and baked lighting;
- Doesn't reproduce for SpeedTrees.