Current employer not exporting to CSV
CiviCRM populates current employer based on what is stored in civicrm_contact.current_employer rather employee/employer of relationship. While adding employee/employer of relationship relationship the form provide is_current employee option, if ticked  civicrm_contact.current_employer is stored with organization name and also same field is used in add/edit contact form. 

For some reason the data for 5 contacts didn't had civicrm_contact.current_employer saved properly, resaving them might populated the field correctly.