usd procedural does not bind materials to instances

[xsisupport]

Describe the bug When I try to load a layered USD file with materials and material assingments which looks like this:

#usda 1.0
(
    endTimeCode = 100
    framesPerSecond = 24
    metersPerUnit = 1
    startTimeCode = 1
subLayers= [
@./domelight1.usd@,
@./layerTest_materialassing.usda@,
@./layerTest_materiallib.usda@,
@./layerTest_boxes.usda@
    ]
    timeCodesPerSecond = 24
    upAxis = "Y"
)

In Maya with MtoA 5.3.1, the light works, the boxes are animated, but the shaders are not applied. Same file renders fine in Houdini with Arnold/Solaris.

To Reproduce layers (1).zip

Expected behavior A clear and concise description of what you expected to happen.

Screenshots

[autodesk-oss-arnold-bot[bot]]

Issue synced internally to ARNOLD-13545