i started a game but only the chess board was viable. no player names and ratings were visible. no warning that’s usually displayed in the first minute to start the game within 30 seconds was displayed.
so i got the warning about starting a game but not moving, but something was wrong with the display, and not on my end.
It sounds like the page had trouble downloading something, threw an exception, etc or just stopped loading. When something like this happens, you should reload. It won't forfeit your game, it usually just fixes things.
A moderator would look at your history before taking action ... in your case, it seems obvious you should not worry about the reminder.