RT's email address showing in one-time CC list

I’m in the process of moving RT 4.0.5 from an old server to a new one.
In the process, I’m also upgrading it to 4.0.23 (and maybe 4.2.x soon
after.) Its mostly going smoothly. However, in the Comment and Reply
screens of the web GUI, under “One-time Cc” and “One-time Bcc”, it
lists RT’s address at the new server.

The old server was cns.cairodurham.org (CNAME of
atlas.cairodurham.org) and the new server is its1.cairodurham.org.
Addresses like rt@cns.cairodurham.org and rt@atlas.cairodurham.org
aren’t showing in the one-time list. Addresses like
rt@its1.cairodurham.org and rt-comment@its1.cairodurham.org do show

In RT_SiteConfig.pm, my RTAddressRegExp is set to:
Set(RTAddressRegexp , '^{rt|help|rt-comment}\@{its1\.|cns\.|atlas\.|}cairodurham.org’);

The script generate-rtaddressregexp suggests this:

Any idea what I missed?

Thanks in advance for any help you can offer.

Jaime Kikpole
Network Administrator
Cairo-Durham Central School District

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