Visit https://de.m.wikipedia.org/wiki/Spezial:Mobile_Optionen
and you will notice the special page is not styled. Likewise for https://fr.m.wikipedia.org/wiki/Sp%C3%A9cial:Liste_de_suivi
This is because module names for special pages are tied to names.
It seems rather than looking for mobile.watchlist.styles and mobile.watchlist.scripts the aliased special page looks for mobile.liste_de_suivi.styles and mobile.liste_de_suivi.scripts
Offending line
$id = explode( '/', strtolower( $title->getText() ) );
in SkinMobile.php
Version: unspecified
Severity: major