Map labels language setting not saved correctly on Windows Phone navigator

Hi,
I'd like to report a bug with WP versoin of Mapfactor Navigator.
The "map labels language" option is not saved accross app restart.
Example:
I use my application in Czech and default option for "map labels" is "app language". So instead of "Warszawa" I see "Varšava", instead "Salzburg" I see "Solnohrad" and many many others.
So I change it in settings to "local names", go back to map and its nice and dandy.
However when I close the app and start again, the map labels are displayed in the "app language". In case my app is in czech, I see Varšava again, when my app is in eg. english, I see Warsaw, Vienna and Prague instead of Warszawa, Wien and Praha.
So I have to navigate into settings > language > map labels language... and even though "local names" are selected it does not work and I need to re-select it again. Afterwards the names are correctly displaed as local names.
So to sum up - the settings menu is displaying correct setting, but the bevavior of the app is "reset" to the default one after app restart.
Hope its clear if not we can discuss in chech :)

EDIT: my phone is lumia 620