To reproduce:
1. Open attached project;
2. Open Scene "Test";
3. Notice that TestLayerObjects with Opaque and Cutout ignores culling mask of blue light source.

Expected result: Opaque and Cutout objects are half green and half red color.
Actual result: Opaque and Cutout objects have blue color as well.

Reproduced in : 5.6.0b8; 5.5.1p3; 5.5.1f1; 5.5.0f3

Note: Picture attached : http://bugs04.unity3d.com/fogfiles/879852_0lg1sel1pcda08j6/case_879852-LightCullingBug.png

Note: happens when camera is in deferred mode and using perspective projection. (also see error message in console - image below)