As it turned out the culprit was the de-provisioning/re-provisioning of the UPSS (which happens during SP backup process). Each time the UPSS was re-provisioned, that mapping dropped. After reaching out to a familiar and trusted resource, Trevor Seward, he was able to determine the root cause. Please see his blog-post for explanation/resolution. http://thesharepointfarm.com/2014/04/name-user-profile-property-mapping-blank-reprovisioning
Tuesday, April 1, 2014
SP 2013 Name Profile Property Disappears After Re-provisioning UPSS (Farm backup)
While working on a prject involving a SharePoint Extranet and a custom .net user provisioning application, I came across an issue where the 'Name' profile property was mapped to a custom AD attribute, however, that mapping would disappear after a full farm backup. This caused us to have to manually or programatically (script) remap the mapping after every backup.