Reproduction steps:
1. Download project "Bugtest.zip" and open in Unity
2. Enter Play mode

Expected: gun has a texture all around the scene (Expected.png)
Actual: parts of a gun are black which are not in front of other objects (Actual.png)

Reproduced on: 5.6.3p2; 2017.1.1f1; 2017.2.0b10; 2017.3.0a7

Note:
Renderer.material.SetShaderPassEnabled("Deferred", false) - tells component not to render in deferred, if set to true works as expected;
Works as expected if "Main Camera" component "Weapon Renderer (Script)" is disabled.