This seems to be a case where the server was correcting for lag. This is not a bug, because your opponent had played his move when his clock had 0.7 seconds remaining. Your computer didn't show it right away, because of the time needed to relay that information (i.e., lag). It's explained in better detail here:
http://support.chess.com/Knowledgebase/Article/View/121/0/what-is-lag-and-what-are-the-colored-lag-indicators-in-live-chess
and here:
http://support.chess.com/Knowledgebase/Article/View/91/13/why-did-the-clock-times-suddenly-change-the-clocks-seem-broken
Remember that the game is not over even when a clock reads 0:00.0. In the future, if your opponent runs out of time, wait for the dialog box that says "Escoban won on time." Only then can you be assured that the server logged the conclusion of the game.
Just played a game in which my opponents timer ran out and I turned around to talk to someone since the game was over, when I looked back my opponent suddenly had 0.7 seconds left on his clock and I lost the game.
This seems a bit silly and unfair. :(
:(((