Hi! This has been the case for a while and I see the same as you. While the new agent for movies works fine for norwegian the agent for TV-series never get the correct metadata when norwegian is the preferred lanuage. I suspect it is beacause of the two norwegian language variants (Bokmål, Nynorsk). Thetvdb supports lanuage variants but Plex does not seem to search correctly…
It would be nice if the Plex team at least could investigate or tell if this will be corrected in the next edition of the agent. I guess they are in a a process to do some changes to the series agent to be more in line with the new movie agent.
I posted a thread earlier about the norwegian problem with tv series metadata:
