Round and round

I'm on an email list (one of many) for which yesterday I received over 80 copies of the identical email - well not quite identical the headers grew which each further email in the sequence and the emailer kindly added a footer to each telling you how to unsubscribe.
What caused amusement to me was an inspection of the headers, it looked to me as if part of the reason for the looping was that the email was regard as spam, the report started off as (34 lines 1321 bytes) as the following spamassassin report:

Content analysis details:   (-3.9 points, 5.0 required)
 pts rule name              description
 ---- ---------------------- --------------------------------------------------
 -2.6 BAYES_00               BODY: Bayesian spam probability is 0 to 1%
 [score: 0.0000]
 -1.3 AWL                    AWL: From: address is in the auto white-list

but 80+ messages later (706 lines 18625 bytes)

Content analysis details:   (-0.4 points, 5.0 required)
 pts rule name              description
 ---- ---------------------- --------------------------------------------------
 0.1 FORGED_RCVD_HELO       Received: contains a forged HELO
 2.5 HEAD_LONG              Message headers are very long
 0.5 DATE_IN_PAST_03_06     Date: is 3 to 6 hours before Received: date
 0.0 UNPARSEABLE_RELAY      Informational: message has unparseable relay lines
 -2.6 BAYES_00               BODY: Bayesian spam probability is 0 to 1%
 [score: 0.0000]
 -1.0 AWL                    AWL: From: address is in the auto white-list

so the more it looped and the spammier it got and more likely it was to loop....as it says

Message headers are very long

hmmmm