I have just switched to 5.6b3 and moved over from multipass to singlepass stereo rendering and I have noticed a measurable increase in the scale of items in a scene.
Can anyone think of what might be causing this. I have checked settings such as the min and max render scale. If I go back to mulitpass everything looks correct.
Any suggestions on what might be causing this?
Random thought: do you modify the perceived world scale in VR by changing local scale on your camera or on something up the hierarchy from it? I do this in my project and I hope 5.6 doesn’t break this because it’s critical for several effects.
We arent modifying the world scale anywhere in the scene. I am still looking into this. I would be interested to know if it effects you as well
Looks like you have the same issue as mine, going into single pass removes the sense of 3d depth perceived by each eye, and no one was able to answer me whether it’s a normal behavior or a bug?!
I posted the same issue here : https://forum.unity3d.com/threads/stereo-single-pass-for-gearvr.453859/
Lots of issues with single pass. Hate to say it but you may want to try deleting your libraries. I had a strange render issue that was fixed by doing that.
I just did like you asked, deleted the library folder, and a new one was rebuilt, i’m on version 5.6 beta 7 now, and guess what? now the single pass stays at the gray screen right after the unity logo, not even launching like it did in previous beta 
At least multipass is still working correctly, i hope this issue gets resolved soon, i really think it will bring a lot of gain to gear vr performance, also vulkan api is still not compatible with gear vr stereoscopic view, it launches but as a mobile game (everything on a single big screen)