I have noticed that some of the games that I have voted for in the past(within 3 months) have lost the votes I gave to them. I vote on every game I play so I know that I've played them before and so when I play a game I like but haven't played in a while the vote has disappeared.
The next time you see this happen, leave a message on my profile with which game it was, and what you think you rated the game, and I'll have a look at the database system.
