UI\MenuItem constructor not called

[WinterSilence]

class MenuItemFoo extends UI\MenuItem
{
    public function __construct()
    {
        file_put_contents('debug.log', 'construct MenuItemFoo');
    }
}
$menu = new Menu('File');
// Class created but `__construct` method not called
$menuItem = $menu->append('Foo', MenuItemFoo::class);