MaterialX material with name "material" fails to render in HdStorm

[pablode]

Description of Issue

Consider following USDA:

#usda 1.0

def Sphere "ball" (
    apiSchemas = ["MaterialBindingAPI"]
)
{
    rel material:binding = </Materials/material>
}

def Scope "Materials"
{
    def Material "material"
    {
        color3f inputs:base_color = (0.2, 0.4, 1)
        token outputs:mtlx:surface.connect = </Materials/material/SS.outputs:surface>

        def Shader "SS"
        {
            uniform token info:id = "ND_standard_surface_surfaceshader"
            color3f inputs:base_color.connect = </Materials/material.inputs:base_color>
            token outputs:surface
        }
    }
}

where a material has the name "material" (which is common).

It fails to render in HdStorm and other renderers using the HdMtlxCreateMtlxDocumentFromHdNetwork function with an exception thrown from the MaterialX library:

Child name is not unique: material

Steps to Reproduce

Open above snippet with usdview

System Information (OS, Hardware)

Windows, RTX 2060

Package Versions

USD v22.11

Build Flags

--materialx --build-variant release --opencolorio --openimageio

[sunyab]

Filed as internal issue #USD-7739