I've got the same problem with the internal IPv6 handoffs:
Received: from owa10.tccsa.net ([208.108.97.33])
by redacted with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
(Exim 4.76)
(envelope-from <gren_cmiller[at]tccsa.net>)
id 1QdrID-0007eh-7D
for redacted; Tue, 05 Jul 2011 00:07:01 +0200
Received: from OWA10.tccsa.net ([fe80::60b0:6f8a:e77c:ea45]) by
OWA10.tccsa.net ([fe80::60b0:6f8a:e77c:ea45%10]) with mapi id 14.01.0218.012;
Mon, 4 Jul 2011 18:05:37 -0400
Even though this was sent to me via IPv4, from the IPv4 address of that host (208.108.97.33), SpamCop does not accept the report because they internally handed it off with IPv6 once. (If I were a spammer, I would start to just add fake IPv6 headers to my mails to avoid SpamCop reports....)
I get that SpamCop may have issues tracing actual IPv6 addresses, but why can it not apply the normal IPv4 mailhost rules here?