Failure with find_reference_node.

[BradWhitlock]

I ran across a strange case where find_reference_node fails when I move mesh domain node to a different node. I would expect that since the new node took ownership of the mesh data, it would serve as the root and ought to basically be the same as the copy case.
Here is a reproducer:

#include <conduit.hpp>
#include <conduit_blueprint_mesh_utils.hpp>

#include <cassert>
#include <iostream>

int main(int argc, char *argv[])
{
  const char *yaml = R"(
mesh:
  coordsets: 
    coords: 
      type: explicit
      values: 
        x: [0.0, 1.0, 2.0, 0.0, 1.0, 2.0, 0.0, 1.0, 2.0]
        y: [0.0, 0.0, 0.0, 1., 1., 1., 2., 2., 2.]
  topologies: 
    topo: 
      type: unstructured
      coordset: coords
      elements:
        shape: quad
        connectivity: [0,1,4,3, 1,2,5,4, 3,4,7,6, 4,5,8,7]
        sizes: [4,4,4,4]
        offsets: [0,4,8,12]
  matsets: 
    mat: 
      topology: topo
      material_map: 
        mat0: 0
        mat1: 1
        mat2: 2
      material_ids: [0, 1, 2, 1, 2]
      volume_fractions: [1., 1., 1., 0.5, 0.5]
      sizes: [1, 1, 1, 2]
      offsets: [0, 1, 2, 3]
      indices: [0, 1, 2, 4, 5]
  fields: 
    elems: 
      topology: topo
      association: element
      values: [0, 1, 2, 3]
  state: 
    cycle: 0
    time: 0.0
    domain_id: 0
)";

  // "Read" the mesh.
  conduit::Node whole;
  whole.parse(yaml);

  // Get the path to the mesh. The path will have the "mesh/" prefix. Ew.
  {
    conduit::Node &mesh = whole["mesh"];
    std::cout << "Path to topologies/topo: " << mesh["topologies/topo"].path() << std::endl;
  }

  { // Use find_reference_node with a copy.
    conduit::Node mesh;
    mesh.set(whole["mesh"]);

    // Get the topo through the matset.
    const conduit::Node *n_topo = conduit::blueprint::mesh::utils::find_reference_node(
     mesh.fetch_existing("matsets/mat"), "topology");
    std::cout << "n_topo = " << (void*)n_topo << std::endl;
    assert(n_topo != nullptr);
    std::cout << "OK!\n";
  }

  { // Use find_reference_node with a moved mesh.
    conduit::Node mesh;
    mesh.move(whole["mesh"]);

    // Get the topo through the matset.
    const conduit::Node *n_topo = conduit::blueprint::mesh::utils::find_reference_node(
     mesh.fetch_existing("matsets/mat"), "topology");
    std::cout << "n_topo = " << (void*)n_topo << std::endl;
    // IT WILL BE NULLPTR AND IT WILL ABORT HERE
    assert(n_topo != nullptr);
    std::cout << "OK!\n";
  }

  return 0;
}