Assigning PointsMaterial to loaded (animated) FBX - three.js

Question

Using this answer I've been able to assign a points material to a loaded GLTF model.
If I apply the same technique to an animated FBX model, the model loads and points material is assigned but the animation no longer works. Presumably because the technique works by duplicating the mesh.
How can I adapt this technique to include the animation?
Using PointsMaterial for loaded GLTF: (working)
const gltfLoader = new GLTFLoader();
gltfLoader.load( 'models/model.gltf', function ( gltf ) {
model = gltf.scene;
let pointsArray = [];
let v3 = new THREE.Vector3();
model.traverse(child => {
if (child.isMesh){
let pos = child.geometry.attributes.position;
for (let i = 0; i < pos.count; i++){
v3.fromBufferAttribute(pos, i);
pointsArray.push(v3.clone());
}
}
});
let particle_model_geometry = new THREE.BufferGeometry().setFromPoints( pointsArray );
particle_model_geometry.center();
particle_model = new THREE.Points( particle_model_geometry, points_material );
scene.add( particle_model );
render();
} );
Usings PointsMaterial for loaded FBX: (not working)
const loader = new FBXLoader();
loader.load( 'models/model.fbx', function ( object ) {
mixer = new THREE.AnimationMixer( object );
const action = mixer.clipAction( object.animations[ 1 ] );
action.play();
let pointsArray = [];
let v3 = new THREE.Vector3();
object.traverse(child => {
if ( child.isMesh ){
let pos = child.geometry.attributes.position;
for (let i = 0; i < pos.count; i++){
v3.fromBufferAttribute( pos, i );
pointsArray.push( v3.clone() );
}
}
});
let particle_model_geometry = new THREE.BufferGeometry().setFromPoints( pointsArray );
particle_model_geometry.center();
particle_model = new THREE.Points( particle_model_geometry, points_material );
scene.add( particle_model );
} );