When using "Save to" and then having "Fast resume" checked - then the files get moved to a directory in the default download location where a new dir is created using %2F insted of "/" in the path you entered.
For instance if you choose save to: "/media/torrents/series/" and your default download directory is "/media/torrents/downloads" then in the default directory this dir is created and the files placed in it: "%2Fmedia%2Ftorrents%2Fseries".
For instance if you choose save to: "/media/torrents/series/" and your default download directory is "/media/torrents/downloads" then in the default directory this dir is created and the files placed in it: "%2Fmedia%2Ftorrents%2Fseries".