Reproduction steps:
1) Open user's attached project
2) Build and run "MainScene v2" scene on the Android device
3) Put device into a GearVR
4) Press "Play Video" button
5) Press back button (on a GearVR itself) twice (this should launch video)
6) Rotate your head
-- Notice that whole video flickers when head (camera) is rotating

Note:
This happens only when video is playing. When it's paused (press back button on a rig once) video doesn't flicker.

Regression appeard in 5.3.5p2