The application service account requires write privileges in order to effectively check the date/time stamp of the file.  Without write privileges, the system will not update the file date/time, thus it will never believe that the file has been changed, thus it will never initiate its sequence.  

The solution is to identify the lowest level FTP directory that contains the file(s) in question and explicitly, i.e. not via a AD group, give the application service account read and write privileges.  This should be done for all application service accounts involved, i.e. teslanetwork, service.staging, and service.production.  Making the change on one of the FTP servers should suffice as DFS replication will propigate the change to the others.