Hi,
Looks like messages are piped through SpamAssassin for processing more than once:
| ubuntu@juju-c4acfb-prod-lists-canonical-com-57:/var/log$ grep <email address hidden> mail.log
| Jan 8 22:59:11 juju-c4acfb-prod-lists-canonical-com-57 postfix/cleanup[23006]: CA46C13B03B: message-id=<email address hidden>
| Jan 8 22:59:11 juju-c4acfb-prod-lists-canonical-com-57 postfix/cleanup[23823]: F06B113B07A: message-id=<email address hidden>
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/cleanup[23006]: A090F13B03B: message-id=<email address hidden>
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/cleanup[23823]: C0E8B13B07A: message-id=<email address hidden>
| ubuntu@juju-c4acfb-prod-lists-canonical-com-57:/var/log$ grep -E 'CA46C13B03B|F06B113B07A|A090F13B03B|C0E8B13B07A' mail.log | sort -k 6
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/smtpd[22985]: A090F13B03B: client=localhost[127.0.0.1]
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/qmgr[18364]: A090F13B03B: from=<email address hidden>, size=3449, nrcpt=4 (queue active)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/cleanup[23006]: A090F13B03B: message-id=<email address hidden>
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/qmgr[18364]: A090F13B03B: removed
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/pipe[21516]: A090F13B03B: to=<email address hidden>, relay=spamassassin, delay=0.13, delays=0.01/0/0/0.13, dsn=2.0.0, status=sent (delivered via spamassassin service)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/pipe[21516]: A090F13B03B: to=<email address hidden>, relay=spamassassin, delay=0.13, delays=0.01/0/0/0.13, dsn=2.0.0, status=sent (delivered via spamassassin service)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/pipe[21516]: A090F13B03B: to=<email address hidden>, relay=spamassassin, delay=0.13, delays=0.01/0/0/0.13, dsn=2.0.0, status=sent (delivered via spamassassin service)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/pipe[21516]: A090F13B03B: to=<email address hidden>, relay=spamassassin, delay=0.13, delays=0.01/0/0/0.13, dsn=2.0.0, status=sent (delivered via spamassassin service)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/qmgr[18364]: C0E8B13B07A: from=<email address hidden>, size=3590, nrcpt=4 (queue active)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/cleanup[23823]: C0E8B13B07A: message-id=<email address hidden>
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/qmgr[18364]: C0E8B13B07A: removed
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/smtp[26054]: C0E8B13B07A: to=<email address hidden>, relay=mx.canonical.com[91.189.95.10]:25, delay=0.12, delays=0.01/0.01/0.06/0.03, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as D60F21A4368)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/smtp[26054]: C0E8B13B07A: to=<email address hidden>, relay=mx.canonical.com[91.189.95.10]:25, delay=0.12, delays=0.01/0.01/0.06/0.03, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as D60F21A4368)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/smtp[26054]: C0E8B13B07A: to=<email address hidden>, relay=mx.canonical.com[91.189.95.10]:25, delay=0.12, delays=0.01/0.01/0.06/0.03, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as D60F21A4368)
| Jan 8 22:59:14 juju-c4acfb-prod-lists-canonical-com-57 postfix/smtp[26054]: C0E8B13B07A: to=<email address hidden>, relay=mx.canonical.com[91.189.95.10]:25, delay=0.12, delays=0.01/0.01/0.06/0.03, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as D60F21A4368)
Let's fix that to only process on incoming.
