I've never heard of that - is it the same player?
reconnecting and losing

No, no one can do such thing. Try clearing your browser's cache and temp files, use the latest versions of firefox or chrome, update your java and flash, and make sure your internet connection is decent and stable.
In the last few days my connection had been disrupted several times as I was going to win a game. Is it possible that my opponent could somehow do this? I can't account for this new phenonemon.