There are a few ways.
Currently, we will try and get it from TVDB as long as their v3 API continues working. With this show, it looks like TMDB needs the TVDB ID added in the external ID section in order to link the 2 entries.
If there is no TVDB connection, it will use TVMaze for the info. It looks it up using the IMDB first, then TVDB. TMDB would need both of those fields to use this lookup.
Lastly, we can manually set the air day and time and we’d handle that via a support ticket. That is the best way so we can manage the support queue.