http://www.cerb4.com/forums/showpost.php?p=4321&postcount=5

Moved to Milestone #20. There may be increased interest from a recent blog post.

Cannot reproduce in dev build 812.

Considering this seemingly could only occur when worker addresses are used as external (customer) addresses, it's most likely not something to worry about. As long as this overall behavior is still possible in the Helpdesk, things like this will never be completely wiped out.

It's best for users to avoid this situation to begin with to the best of their ability.