mistake on my side.
your scene renders correctly, with standard renderer.
my original scene renders fine as well.
the convex hull keeps appearing when rendering with vray RT,
in my first post i misplaced the render engines. i mentioned vray standard and vray RT,
it supposed to be VrayRT CPU and VrayRT GPU.
i remember from the past that RT on CPU used to be very close to vray standard in terms of rendering results, hence the expectations regarding FPP integration