GLTFLoader seems to use the origin blob url unexpectedly

I was trying to use the LoadingManager class to let my gltfloader use the local blob assets, however, the output shows that the gltfloader still tries to load the wrong URL, it should use blobs URLs created by URL.createObjectURL isn’t it?

here’s my code:

    const manager = new LoadingManager();
    manager.setURLModifier((url) => {
        // get blob
        const blob = this.blobs.blobMap.get('currBlob');
        url = URL.createObjectURL(blob);
        return url;
   this.loadingManager = manager;
   // some logic...

   const loader = new GLTFLoader(this.loadingManager);
        (gltf) => {

This is quite strange, the output shows that the gltfloader was trying to load ‘currBlob’ during loading files, here’s the screen shot: