Repro steps:
1. Open "MaterialPropertyBlockTest" project
2. Open "Scene" scene
3. Check the inspector and notice that the left character has the material block script
4. Press play
5. Observe that two characters have material block property

Note: If you set the main camera at a certain angle (for example X: 2.3, Y:0, Z:-3.09) material block property works properly

Actual behavior: Object with a material block property causes other object's material to block at a certain camera angle
Expected behavior: Only object with the material block property should block the material

Reproduced on: 5.4.0f3, 5.4.0p1, 5.5.0a5
Did not reproduce on: 5.3.6p2