When an environment is copied, the current method is to blank the email addresses in the LogisticsElectronicAddress table. This means that when the BYOD DMF export is run for Party Contacts or Worker Contacts it fails as the locator is a required field. The only way to stop this from happening currently is to reload all the email addresses after an environment has been copied or by removing the records completely. The environment copy functionality should allow you to remove all email address records (rather than make them blank) or copy across the email addresses in the LogisticsElectronicAddress table.