Cannot maintain texture when generating instanceable USD from URDF files

Hello, community!

I have some trouble keeping the texture for instanceable USD objects generated from their URDF files.

lemon.zip (8.7 MB)

For an object like the above one, I have its visual and collision meshes as well as textures (stored as file material_0.*) and the URDF file. I can successfully generate a USD stage containing this object with textures using following code (the generated USD file is stored in usd_dest_path/model.usd)

from omni.isaac.kit import SimulationApp
simulation_app = SimulationApp({"headless": True})

from omni.isaac.core import World
from omni.isaac.core.utils.extensions import get_extension_path_from_name
from omni.isaac.urdf import _urdf
from omni.isaac.core.utils.stage import save_stage
import omni.kit.commands

world = World()

world.scene.add_default_ground_plane()
# Acquire the URDF extension interface
urdf_interface = _urdf.acquire_urdf_interface()
# Set the settings in the import config
import_config = _urdf.ImportConfig()
import_config.make_instanceable = False
import_config.merge_fixed_joints = False
import_config.convex_decomp = False
import_config.import_inertia_tensor = True
import_config.fix_base = False
import_config.make_default_prim = True
import_config.self_collision = False
import_config.default_drive_type = _urdf.UrdfJointTargetType.JOINT_DRIVE_POSITION

result, prim_path = omni.kit.commands.execute("URDFParseAndImportFile", urdf_path='model.urdf', import_config=import_config, dest_path='usd_dest_path/model.usd')

simulation_app.close()

However, when I try to generate the instanceable USD file, I have tried either setting make_instanceable to True in this code or using the convert_asset_instanceable from this doc to convert the above generated model.usd (which generates the file usd_dest_path/model_instanceable_withxform.usd), the texture just not display. More wierdly, when using the method of converting asset to instanceable, usd_dest_path/model_instanceable_withxform_meshes.usd (which is the reference of the instanceable USD) does contain the texture.

Am I missing something here?