Thanks a lot for checking.
I experienced a similar issue where only the left eye was rendered, depending on where the prop was placed in the scene, and I thought this was caused by the physical scale of the render window but this might just be a side-effect of the bug.
IIRC the problem was that the props were always culled because the clipping range of the vtkCamera was wrong for the right eye. Can you try adding the following to your main application to see if it fixes the issue?
renderer->RemoveCuller(renderer->GetCullers()->GetLastItem());