Hi!
Since
https://gerrit.wikimedia.org/r/#/c/94899/
(which was deployed to all Wikipedias with wmf6 on December 12) there is
more than one class per inter-language link, so in case your wiki has a
fork of the script which add stars to featured articles in other languages
("LinkFA"), it may have to be fixed as in
https://en.wikipedia.org/wiki/MediaWiki:Common.js?diff=585965732
See also:
https://en.wikipedia.org/wiki/MediaWiki_talk:Common.js#LinkFA_is_broken
Helder