New to Sonarr, working solidly except for it refusing to import downloads of one series

Sorry, misread that. Given that you said there is nothing in Sonarr’s Activity Queue it lead me to think Sonarr/SAB were misconfigured. Is there anything in Activity Queue for this episode? It sounds like a naming issue (Scene Naming (TVDB Naming Conflicts)) but if its not in Activity → Queue make sure a category is set for TV shows in SAB and Sonarr is set to use the same category. Don’t use Drone Factory for importing from SAB.

Please open a new thread with info on which download client you’re using and the ((trace logs)).