Your menu type is:
'menu-item-type' => 'Custom',
But if we look in wp_update_nav_menu_item
:
if ( 'custom' != $args['menu-item-type'] ) {
custom != Custom
, so your URL gets stripped
Your menu type is:
'menu-item-type' => 'Custom',
But if we look in wp_update_nav_menu_item
:
if ( 'custom' != $args['menu-item-type'] ) {
custom != Custom
, so your URL gets stripped