container.instantiateModelsToScene() fails when container.createRootMesh() node is parented to another node

After loading a resource into a container and creating a root node through container.createRootMesh(), the call to container.instantiateModelsToScene() will fail with the error “can’t access property “skeleton”, r[n[u.uniqueId]] is undefined” when the root node has been parented to another TransformNode.

I’ve reproduce the bug in this playground.

https://www.babylonjs-playground.com/#S7E00P#16

The instantiateModelsToScene method will instantiate the hierarchy of loaded meshes only for meshes that don’t have a parent: there’s no such mesh after you parent the root mesh to the transformNode, leading to a bug when skeletons are processed by instantiateModelsToScene.

You should parent to the transformNode after you call instantiateModelsToScene.