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