On visiting https://meta.wikimedia.org/w/index.php?title=Special:Translate&action=page&group=Centralnotice-tgroup-FR2014_translations&language=es&filter= to translate banner messages, the group showed up as empty (see screenshot). This was happening for multiple users. The messages actually being displayed in banners were unaffected.
After some experimenting, I found that after visiting https://meta.wikimedia.org/wiki/Special:CentralNoticeBanners/Edit/FR2014_translations, the messages were restored to the Translate interface.
The same thing also happened twice in the past month with the banner FR2015_translations.
Not urgent, as we now know the workaround in case it happens again, but it would be nice to figure out what's going wrong here.