Include parent and child in category url

Question

I've seen a lot of questions like this, bot none that could solve my problem.

For example: How to include parent terms in hierarchical taxonomy URLs?

I've created a custom category with the register_taxonomy but could't make it work...

I can show my parent and child in the url now, but the parent doesn't matters...

What I mean is that this: http://localhost/collection/foo/childslug/ is the same as http://localhost/collection/bar/childslug/

Is that normal?

BTW: I've registered like this:

$args = array(
        'hierarchical'      => true,
        'labels'            => $labels,
        'show_ui'           => true,
        'show_admin_column' => true,
        'query_var'         => true,
        'public'            => true,
        'rewrite'           => array( 'hierarchical' => true, 'slug' => 'collectie' ),
    );