IMP adding and extra @ to unqualified addresses

[Liam Hoekenga]

We're having a problem with Horde 1.2.6 / IMP 2.2.6 - it's adding an extra
@ to unqualified email addresses.

Everything looks ok in the message header, but if we look at the mail log,
sendmail is getting passed "user@" instead of just "user"

Aug  7 11:04:15 babel.web.itd.umich.edu sendmail[26523]: LAA26523:
to=liamr@, ctladdr=liamr@umich.edu (60001/60001), delay=00:00:00, xdelay=00:00:00,
mailer=hub, relay=smtp.itd.umich.edu. [141.211.2.163], stat=Sent (LAA11529
Message accepted for delivery)

the sendmail installation on our mailhub is automatically taking on
"@umich.edu" for anything that doesn't have an "@blah.blah" style suffix.
So, we're ending up with it trying to deliever to liamr@@umich.edu.

This worked ok with previous releases.  I'm not sure what's up.

Any ideas?

Liam Hoekenga
UofM Webmaster Team