Yeah this has happened to me. The only thing I do know is that sometimes it just really screws up with the time display, but only when the person has like 120 or less minutes.
Sometimes what it says on your display of ongoing games is completely different than what it says when you actually click on the game.
All you can do is complain and check more carefully when time gets into "the minutes".
At the moment I have one game in progress (one move per day game). when I went to make my move I found that my opponent had not yet made his move and had 26 minutes left to make that move. So I went off and did something else and came back about 30 minutes later only to find that he now had 57 minutes on his clock!!
Can anyone tell me what the hell is going on here ?
Just checked and it was 9 minutes and now its 37 minutes.
Many thanks