I believe it is from the file that had the members in that you loaded. It looks like you just missed the step of filling in code. Go back to the action that loaded the members, click Edit, and map the code to the appropriate column in the file.
Go to actions and find the appropriate action named like import into G3 Location from xyz.csv and map the Location codes in the code and select code in the items uniquely identify by code only. and run the action.(You have to delete your previously imported data by un-assigning the parent G2 Country and assign it back before importing.) Good luck!