Add you OSIG file in Build → Android → java → assets
Export as Android → ETC2
Notice when you start the app → insert into the Gearvr when prompted then put on the gear for a split second you see the scene not in stereo then the screen goes black and a split second later it returns as expected (stereo).
Occurs all the time on every UE4.9 project on my Note 4 Exynos chipset device.
I was able to reproduce this in 4.9 and our latest 4.11 branch. I was able to verify that this was not the case with 4.8 and have submitted UE-21714 for this to be investigated. There is no ETA on when this will be addressed, but I will post back here once I have any updates to pass along.