First thing that comes to mind is whether the textures are larger than 2048x2048 or not a power of 2 (i.e. 256, 512, 1024, etc.)? The Note 4 can only handle texture sizes in powers of 2 up to a maximum of 2048.
GearVR Best Practices: Texture Considerations
Not sure if that’s it as I’m figuring all of this out too, yet hope it helps if so.