monoscopic is broken (solved)

Oculus Utilities for Unity 1.26.0
Unity 2018.1.1f1

OVRManager.instance.monoscopic = true;
OVRPlugin.monoscopic = true;

On Windows setting monoscopic to true produces now a double image (an error in the projection function ?) 
Someone reported in another discussion that on gearvr setting monoscopic to true has no effect whatsoever.

I really need monoscopic: I am adding 3d objects to a spherical picture.

The "monoscopic" function until recently did perfectly the job.
Can we have the function back ? 

Thanks, really.