I'm not home right now and can't test this.
I'll give feedback later.
However, I have configured TMDB to give me the synopses in Portuguese (as seen in the image I posted).
In fact, TMDB is not configurable in the Seren addon for any language as it uses the Kodi interface language.
Other addons allow this.
For example, the FEN addon (not FEN Light) allows you to configure TMDB for any language regardless of the Kodi interface language.
Another setting I have on my Kodi is to display the original name of the film (I don't like translated titles)
I think a4kScrapers shouldn't translate the name of the movie to scrape using the Kodi interface language, as it will look for something that doesn't exist.
It should be the other way around!
Always scrape out the original name of the film!
I can't remember now, but I don't think I've ever had this problem before!
I've been using Kodi for several years and Seren, configured this way, and I've never had this problem...
Later I will test the behavior of TVDB.
THANKS!