Some email addresses seem to break RT2 reply messages

Hi all,
I thought this was previously covered so I searched the archives but could
not find a related thread.

I am using RT 2.0.8 with sendmail on a RH 7.1 system. When users with a
either a long email address or an address with a dash character (I haven’t
figured out which is the problem) submit a message to RT a ticket is
generated and the reply is generated but sendmail replies with an error
email message. The error from sendmail shows the email address used is only
half of the address. So, instead of the
address was joeschmo@automated-.

Has anyone else seen this problem? Any ideas or solutions?