GearVR 360 image loading screen issue

Hello, 
I have one issue.

I would like to look at 360 degree images all while loading.

When the scene changes, the 360-degree loading image is not normally displayed.

When you look around with GearVR, 
Only one frame from the front you see is displayed on the screen. 
It looks like a rectangle instead of 360 image. 
Everything except the rectangle looks black.

I am using AsyncOperation.allowSceneActivation. 
The loading screen image uses a 360 degree 2k image. 
I use Unity 5.6.2f1 personal version.

Thank you. 
Gordon Shin.