Since I downloaded the new version (2.2.4 - Warpup III) my rating and the ratings of all the AI are NaN. I tried deleting and reinstalling from the App Store, and that did reset all the game info, but the ratings are still NaN and playing one game didn't change it.
I have one other report of a player whose rating is NaN; in that case, they recently changed Game Center IDs, so their win/loss rating was reset. I'm not sure why the rating would be displayed as NaN, though - that should never happen.
I'm not seeing this here. Can you send me feedback from in-game? That will include a report on some internal game state that might help me understand what's going on.