Re[4]: Pigeonhole redirect is adding a message-id header when it already exists

Oct 1 13:31:46 xxxx sendmail[30321]: 291BVjjx030318: to=xxxx@gmail.com, delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122536, relay=gmail-smtp-in.l.google.com. [142.250.102.27], dsn=2.0.0, stat=Sent (OK 1664623906 gs19-20020a1709072d1300b00777a40d515dsi4096082ejc.456 - gsmtp)

I just tested for you, enabled the sieve forward, send test mail and the forward is being accepted by google.

Thanks for the test. However, does your test mail had a "bogus" Message-ID header in it like I tried to explain ?

For example try to send a mail that has the following Message-ID header:

Message-ID: 1883biz_pay_after_purchase:0:0_572392900$ae7ed6e4d53b424c84aaf83b30c507e7