Well, these files are NOT being created by the torrent client.
I have not run that program since I last wrote, and these files are STILL being created (every day at 9:10am!). Each is about the same size (222M) and has the same kind of content as described here already.
Maybe this will help... http://mudshark.com/t$m_files.png
What's running on this PC?
VIA RAID tool