osTicket Version v1.9.5 (ecb4f89)Web Server Software Apache/2.4.10 (Debian)MySQL Version 5.5.40PHP Version 5.6.4-1If there is a valid AD user in the search DN who does not have an email address assigned in AD and has never interacted with osticket and they login to the client web page, they are assigned the first person who is registered as a authorised client in osticket.... or at least it does in my case