Model I/O USD(C/A) export is buggy, how to export SCNScene to USD?

I have been trying to export a SNCScene to USDC or USDA by using Model I/O, since these function calls:

print("can export usdc: \(MDLAsset.canExportFileExtension("usdc"))")
print("can export usda: \(MDLAsset.canExportFileExtension("usda"))")

both print "True". Here are my steps:

let fileMan = FileManager.default
   
    do {
      let userDocsDir = try fileMan.url(for: .documentDirectory,
                                        in: .userDomainMask,
                                        appropriateFor: nil, create: true)

      let exportsDir = userDocsDir.appendingPathComponent("exports",
                                                          isDirectory: true)

     
      try fileMan.createDirectory(at: exportsDir,
                                  withIntermediateDirectories: true,
                                  attributes: nil)
     
      let uuid = UUID.init().uuidString
      let exportName = exportsDir.appendingPathComponent(uuid,
                                                         isDirectory: false)

      let exportFileUSDC = exportName.appendingPathExtension("usdc")
      let exportFileUSDA = exportName.appendingPathExtension("usda")

      let newScene = SCNScene()
      let cubeGeom = SCNBox(width: 1, height: 1, length: 1, chamferRadius: 0)
     
      cubeGeom.materials[0] = SCNMaterial()
      cubeGeom.firstMaterial!.diffuse.contents = UIColor.red
      cubeGeom.firstMaterial!.name = "red"
      let box = SCNNode(geometry: cubeGeom)
   
      newScene.rootNode.addChildNode(box)

      let asset = MDLAsset(scnScene: newScene)

      print(asset)
      print(newScene)
     
      try asset.export(to: exportFileUSDC)
      try asset.export(to: exportFileUSDA)
    }
    catch {
      log.error("\(error.localizedDescription)")
    }

This code, although it compiles and runs without throwing exceptions, it produces buggy USDA/USDC files, in which the materials are absent and which, if opened by double-clicking on them, crash XCode with the following error:

"Assertion failed: (0 && “MTLPatchTable Creation Failed”), function Create, file /BuildRoot/Library/Caches/com.apple.xbs/Sources/SceneKit/SceneKit-470/lib/libOsd/sources/opensubdiv/osd/mtlPatchTable.mm, line 97."

My research shows that I shouldn't be doing anything wrong, but could someone take a look and help me out, e.g. tell me if I'm doing something wrong in these steps? You can try and run the above code for yourself.