function emailleftappend($content){
$content = preg_replace_callback('/(?<=get\/)(.*?)-(.*?)(?=\/">)/', function ($m) {
return sanitize_title($m[1]). '-'. sanitize_title($m[2]); }, $content);
return $content;
}
add_filter('the_content', 'emailleftappend');
Наконец исправлено.