I'm french and I saw some error in messages displayed when the form was uncomplete during submit in the french translation.
I've tried to edit with poedit but the messages are still the same.
To understand why, I' took the language folder out from the plugin folder (thinking messages would not be displayed at all) but they are.
I can't figure out how messages can be displayed in french as the .po and the .mo files are not in the plugin folder.
Do you follow me ?