Navigo card fails to add to Apple Wallet on iPhone after restore

Hi. I can't find a french equivalent of this forum so I'll ask here anyway. Last weekend I reset my now backup iPhone, an iPhone 13 mini, as I usually do every once in a while. After copying my iPhone 17 contents to the 13 mini (again, I'm used to do this and never had any problems as I always decline transferring my Wallet app's contents as well as eSIMs), the Wallet app in my iPhone 17 asked me to delete my Navigo card (my travel card for people in the Paris, France area) and add it again. It successfully deleted itself, sees I used to have a Navigo travel card with 2 unused train tickets, but every time I tried to restore it it fails with an error message without an error code or anything useful. I tried contacting Ile de France Mobilités (the company issuing the Navigo card) but so far they've been super unhelpful. It just occured to me it could be an Apple Wallet issue, not an issue from their app. I tried adding it on my (now unused) iPhone SE 2nd gen, as well as the 13 mini, but I'm getting the exact same error message as on the 17.

Can anyone help me? I can't even go to an Apple store in Paris to have this issue fixed (except on weekends) as my physical navigo pass (loaded with a yearly Navigo pass for my suburbian area which doesn't include the city of Paris) doesn't allow single tickets to be added to it, contrarily to the Wallet app, for some reason.

Thanks in advance.