One or more of the URLs you've entered is a series page. LitKeeper will download every chapter from that series and merge it with the other URLs. This may produce a large file and take longer to complete.
Author URLs can't be combined
Author profile URLs queue every story from that author individually — they can't be merged into a single combined file. Remove the author URL and use the main field on its own to scan an author's profile.
Queue all stories from this author?
LitKeeper will scan the author's profile and queue every published story. Each one is downloaded individually — this may take time for prolific authors.