Reproduction steps:
1) Download and open user's attached project
2) Build and run "scene vr" scene on an Android device compatible with Gear VR
3) Put device into Gear VR
-- Notice that right eye is not rendered

Note:
I was able to reproduce this issue on both OpenGL ES and Vulkan, but there are many users who report that this only happens on Vulkan API.

Workaround:
If you turn on Unity's splash screen both eyes will be rendered as expected

Reproduced with:
2017.1.0b1, 5.6.0p1, 5.6.0b7

DUT:
Samsung Galaxy S7, Adreno 530, Android 7.0
Samsung Galaxy S7, Mali-T880, Android 7.0
Samsung Galaxy S6 Edge, Mali-T760, Android 6.0