I've configured a set of achievements for my iOS game in both English and Spanish through iTunes Connect and now I'm testing them on Sandbox mode in my device (set in Spanish) with a Sandbox tester set to use the Spanish iTunes store. However, when I unlock these achievements in my device the messages appear in English instead of Spanish and with the Game Center icon instead of the one I set up.
Is this an expected behavior because I'm testing it in Sandbox mode and as soon as the game goes live the achievements will be properly shown and localized or is something wrong?
Solution here (Missing localization configuration in Info.plist.xml file). However with every achievement unlock the GC icon is shown. And that it's how it is...