Custom post type not saved in the new custom table

Hi,
i've successfully created a new custom table named 'collaborateur_table' with some fields.
I've a custom post type named 'collaborateur' with fields created like that :

function get_meta_box_collaborateur( $meta_boxes ) {
        $meta_boxes[]= array(
        'id' =>   'creation_collaborateur',
        'title' => esc_html__( 'Fiche collaborateur', 'textdomain' ),
        'post_types' => array( 'collaborateur' ),
        'context' => 'advanced',
        'priority' => 'default',
        'autosave' => false,
        'storage_type' => 'custom_table',    
        'table'        => 'collaborateur_table', // my custom table name
        'fields' => array(
array(
                'id' => 'title',
                'type' => 'text',
                'name' => esc_html__( 'title', 'textdomain' ),
                ),
array(
                'id' => 'nom',
                'type' => 'text',
                'name' => esc_html__( 'Nom', 'textdomain' ),
                ),
[ etc...]
         ),

    );

    return  $meta_boxes;
}
add_filter( 'rwmb_meta_boxes', 'get_meta_box_collaborateur' );

Everything is correctly displayed
But when i publish a new post type 'collaborateur', only the title is registered in the wp_posts table. No new entries is registered in my custom_table.
Did I forget something to be able to save my custom fields in my new table ?