I life in germany and we have special characters here, like äöü. They are not supported in the city names. Maybe it's the font or something else? A simple way would be to add an option to show/hide the city name - or change it's color, so that I can make it black on black.
Yes, it is a font issue. I'll try to find geolocation service which provides en characters only.
But there is an ability to hide the city name, the checkbox "Show current city"