In February this year we stopped matching completed recordings to thetvdb (see EPG metadata is now retained for DVR recordings), because that was leading to missed recordings or duplicate recordings
If you have not started with a new DVR dedicated set of libraries for TV and Film after this change, then automatching with tvdb may still happen because of the existing shows in the library. The tvdb continues to be used if the show is already in the library from the time before this February 2020 change.
I have raised this with the development team to see if we can stop it doing that
