Torrent file created from magnet link can't be loaded.
So, when you run TT with a magnet link, it generates a .torrent file in the running directory. Unfortunately, this file can't be subsequently loaded in place of the magnet link. This is because the .torrent file created is of the contents of the 'info' dictionary only ( https://wiki.theory.org/BitTorrentSpecification#Metainfo_File_Structure ).
What should be done is to generate a proper .torrent file by: -Encapsulating the data written now inside an 'info' dictionary. -Add in the announce and announce-list (if any) that were provided by the magnet-link
(I'm putting up this issue in case anyone else wants to take a crack at it, or failing that, to remind myself of the details when I have free time to program later)