Not really sure if this would be classed as a bug so much as an oversight but (at least) the last 3 versions of CCleaner, after a cleaning, wipe out any playlists made by a user in the DivX desktop video player.
I'm not 100% sure, but I *think* the file being deleted is in %appdata%/DivX/Player/ and the file is Media Library (with no extension).