This is due to the fact static strings flagged translated ( _("string") notation) are not translated when they are static only if they are not inside a dll.
When they are static inside a dll, the dictionary is already loaded, and the constructor translate them.
Therefore they can be translated twice in dialogs are calling wxGetTranslation to show them, if the application is run from kicad.
But if the application is run as stand alone, the translation is made only once (as expected).