I have attached an explicative image at the bottom of this question.
I have this issue both in GoogleVR 0.8.0 and the latest 1.0.1 (because I have updated to check if it fixed the issue).
The provided demo scene of GoogleVR is working well!
Also, the central vertical line that separates the left and right cameras is cut at the middle when build into Android.
I think this issue has happened after updating the Smartphone to Android 6.0 Marshmallow (CyanogenMod 13.0), on Samsung S4.
I have looked everywhere and recompiled after changing different values, but I have not found were the problem could be!