The google VR plugin is expecting you to be using 2 x lenses. Hence why the plguin likes to use stereoscopic vision.
When you are using the command “Stereo off”, you are going against Google VR plugin’s wishes. The lenses already have a decided resolution and how they share the screen so all you are getting is one image that fits half the screen.
As for a solution, I am not sure.
I’m guessing you’re trying to create a “VR vision activating in 3… 2… 1…” sort of thing. But I have a feeling this command on it’s own is not going to achieve this.