Taking a look at a specific series (American Idol 2002), it does not show all available seasons to be requested. Looking at the linked TVDB listing I can see 24 seasons but Seerr is only showing up to Season 15.
Looking through the logs it looks like Series searches use TMDB while Sonarr uses TVDB. TMDB has the Series split into two Series, one from 2002 and a second that started in 2018. Any ideas how to reconcile this?
Seerr v3.0.1