Hi @JulienVDC,
That is an upstream issue, actually.
In other words, it is an issue with osTicket itself.
When they implemented customizable Ticket “queues” around v.11 they broke a bunch of stuff to do with translations, and I don’t think they’ve managed to sort out how they are going to fix those things yet.
If you want to see for yourself, open my vanilla osTicket 1.14.3 demo Ticket Status page:
https://osticketawesome.com/o/1.14.3/scp/lists.php?id=1
Add a French translation for one of the custom statuses (e.g. To Be Invoiced).
Now go to the Profile > Preferences page:
https://osticketawesome.com/o/1.14.3/scp/profile.php#preferences
Set the Preferred Language to French.
Now go to the Open queue:
https://osticketawesome.com/o/1.14.3/scp/tickets.php?queue=1
Note that the translation is still missing from the Ticket Status drop-down menu.
In fact, this issue continues to exist in v1.15.2.
If you want, you can report this issue on GitHub:
https://github.com/osTicket/osTicket/issues
I would do so myself, but I already have a related issue report (“Translations Missing“) from October of 2019 that is still open:
https://github.com/osTicket/osTicket/issues/5098
I wish I could do more, but this is far beyond my particular skill set. And so, we wait.