Quick node in View3D can make rendering unstable

The lancelot scene lighting/colors.qml is unstable. I have boiled the issue down to the attached c2.qml file: When rendered, sometimes the red cube will show up, sometimes it won't.

Seems to happen on all platforms and RHI backends with OpenGL RHI backend.

The extra View3D (blue cube) is also required; cannot reproduce the issue if there is only on View3D object.