Older data missing from skyhook

Sonarr version (exact version): 4.0.9.2244
Mono version (if Sonarr is not running on Windows): 4.0.9.2244 by [onedr0p]
OS:
Debug logs:
Description of issue:

I got a serie “Faites entrer l’accusé” (TVDB 84095 Faites entrer l'accusé - TheTVDB.com ) that have a lot of missing episode titles. I’ve read some information about recently aired episode and the fact that because of API regulation you sometimes have to wait 24 ou 48h to get the episode title and description in “skyhook” ( https://skyhook.sonarr.tv/v1/tvdb/shows/en/84095 ).

In this case for example, the TBA episode titles were aired for some more than 3-4 years ago and the data is missing.

All the information are present in the TVDB database. I’ve tried for some weeks to push the “Update selected series” button and unfortunately after waiting it appears that it’s not up to date.

Is this a bug? How can I proceed to get the episode title?

Thank you in advance for your help!

Taking a guess: the metadata is French. Sonarr only uses the English metadata from thetvdb.