One profile doesn't show any flag?
For some accounts, (especially old ones), their flag won't appear until a few hours after they play the game for the first time after the 2.08 update.
If still no flag appears, then there's two possibilities: Either they're playing from a country that I didn't enter a flag for (there's a few small ones, like Antarctica that I didn't bother with), or the IP-to-country program I used didn't know where they were.