I had the same thing happen here:
http://en.lichess.org/4S9FfURjhlSWIt's a bit frustrating when an update makes the server crash for half an hour and yet somehow the time keeps going or somehow your opponent gets back to the game faster than you do and they get the claim victory option. Not sure there's really anything that could be done about that except aborting all games on a server restart which might annoy people more.