Upstream released 0.65.1, which has some major improvements (IPv6 source address, mailbot is able to *not* quote the message), so it would be nice if gentoo would have the new version. As 0.65.2 is out, you should take this one. I compiled it with a copy of the 0.65.0 ebuild, this worked. So it's just a version bump.
thanks for your contribution. please always use full package atoms at the beginning of the summary. in this case mail-mta/courier thanks.
done