I took the liberty to transcribe this topic into an actual issue. Do not hesitate to answer there in order to find the right resolution for this.
https://gitlab.kitware.com/vtk/vtk/issues/17727
Thanks @lassoan @estan @simonesneault for your investigation and debugs.
This somehow passed under my radar in september.
QVTKOpenGLWidgetWarningOnlyForStereoRendering
