Suddenly my watch face date is (randomly) shown in English

Hi, I'm saying suddenly because the watch face was last updated in December 2023 and starting last month, I have people saying although their language is set to something else than English, the date is in English. I also had that problem myself and it went away by itself, then came back! Like currently, although my watch language is French, the date is displayed as "FRI 19 APR". Rebooting the watch, changing the language to English then back to French didn't help. I tried to simulate the problem in the simulator but the date there is always in the right format. Not sure how I can debug this.

For example, the day is read as such

var rezStrings = Rez.Strings;

resourceArray = [
   rezStrings.Sun,
   rezStrings.Mon,
   rezStrings.Tue,
   rezStrings.Wed,
   rezStrings.Thu,
   rezStrings.Fri,
   rezStrings.Sat
];
mDayOfWeekString = Ui.loadResource(resourceArray[mDayOfWeek - 1]).toUpper();

This is how the days are defined in strings.fre

<string id="Sun">Dim</string>
<string id="Mon">Lun</string>
<string id="Tue">Mar</string>
<string id="Wed">Mer</string>
<string id="Thu">Jeu</string>
<string id="Fri">Ven</string>
<string id="Sat">Sam</string>

This is the only line on the watch face that is internationalized, so maybe the whole string file is ignored? My watch is a Fenix 7S Pro.

Anybody has seen this or would know where I could start to debug this?

Thanks