How can we improve WHMCS?

Before version 8, if an email came in with a ticket number in the subject line that reply would be added to the thread. This would be the case for situations such as a distribution group being CC'ed on a ticket and one of the members of that group replying. Before version 8 this worked exactly as expected, now the ticket import fails whenever the sender is not already in WHMCS. This is an absolute deal breaking, find a new platform level problem for us since emails from clients are getting missed unless we're constantly monitoring the ticket import log.