3D Tileset Loads and fades

When setting up a (local) server, as described in the 3D Tiles Samples instructions, then it should be possible to load this tileset with this sandcastle code:

const viewer = new Cesium.Viewer("cesiumContainer");
var tilesetTree = viewer.scene.primitives.add(
  new Cesium.Cesium3DTileset({
    url: "http://localhost:8003/1.0/TilesetWithTreeBillboards/tileset.json",
  })
);

tilesetTree.readyPromise.then(function (tilesetTree) {
  viewer.camera.flyToBoundingSphere(tilesetTree.root.boundingSphere);
});

The result should look like the following screenshot:

Can you describe in more detail what you mean by “fading quickly”?