To reproduce:
1. Open the attached project;
2. Create a new material;
3. In the Inspector Window, notice the color of the new material;
4. Change the color of ProjectorsMaterial.mat;
5. Press on the new material to see its color change in the inspector.

Expected result: the color of the new material is not affected by the material used for the Projector.
Actual result: color of the new material is changed to the color of the material used for the Projector.

Note: it only affects preview of the Material, it does not change the color of material.

Reproduced on: 2017.1.0b2, 2017.1.1p4, 2017.2.0f2, 2017.3.0b3.
Not reproduced on: 5.6.3p4, 2017.1.0b1.
Regression introduced on: 2017.1.0b2.

Fixed on 2017.3.0b8.