Url of navigation menu item of alternative type removed

[stephenh1988]

When creating a new navigation menu item with wp_update_nav_menu_item the url is removed if the type of the item is not 'custom'. If the type of the item is 'taxonomy' or 'post_type', the url is then set appropriately. However, if the item has a type other than 'custom','taxonomy', or 'post_type' the menu item is saved without an url.

wp-includes/nav-menu.php L314

if ( 'custom' != $args['menu-item-type'] ) {
     /* if non-custom menu item, then:
     * use original object's URL
     * blank default title to sync with original object's
     */

     $args['menu-item-url'] = '';