Yes, something is not right in the 3D model.
There are some special coding in the BFC app to handle materials, probably to work around and "fix" what is wrong in the model. Lets just close this issue and forget about it.
Thanks again for looking into this.
/A
......
loader.load('./resources/models/' + model_file + '.json', function (geometry, materials) {
var modelMaterial = new THREE.MeshFaceMaterial(materials),
model = new THREE.Mesh(geometry, modelMaterial);
.....