1) Open attached project "EmulationBug"
2) Open scene "Demo"
3) Set build target to Android
4) Make sure that Graphics Emulation is set to GLES 2.0 and Teir 1 Hardware
--- You should see a grey sphere, even though its shader has #pragma exclude_renderers gles
--- On an actual GLES 2 device sphere is magenta "shader not working" color
--- Same thing is expected with graphics emulation

Note:
Project includes two shader versions, Bug5-4 and Bug5-3. Bug5-4 does not work in Unity 5.3 because it uses UnityObjectToClipPos.