It looks like a player’s rating is not stored along the information for a specific game, but is being derived from the current rating when displaying his or her games’ history. This leads to incorrect display of information on previous games, if that player’s rating has changed over time.
Simply spoken, this seems to be a violation of ‘document integrity’, if you regard the correct rating of the players a property of the game (at the time the game was played) and not of the players.
In the future we’ll be recording the rank of the players for the game but you are right… we currently do not. However… the rank graph for each player does record this information so it’s possible to view it there.
if you open a game you usually get to see what rank you had when playing it… so are you sure you aren’t saving that info somewhere?
Some information is cached on the service the controls the game state and other information is store just in the application database itself which is why you’ll sometimes see some disparity.