Some taxonomies add a custom rewrite rule to their newly registered taxonomies. In order to add the correct translated rewrite base you need to use the following filter:
add_filter( 'wordpress_multilingual_multisite_taxonomy_base', 'we_change_faq_topic_taxonomy_base', 20, 3 ); function we_change_faq_topic_taxonomy_base( $base, $taxonomy, $blog_id ) { if($taxonomy !== "faq_topics") { return $base; } if($blog_id !== 11) { return $base; } $base = 'wissensdatenbank/topics/'; return $base; }