Is there a gmail SMTP expert in the house?

Gmail just bounced some mail to the RFC822 From: address rather than the
RFC821 MAIL FROM:. And won't let you
report a problem unless you have a gmail account.

Due to an off-list reply, it's been determined that somebody adgered
the Received: headers, causing an error in identifying the real bounce

Grungy details: After somebody generated a bounce, it took 3 hops through
10.x space inside gmail before arriving at our mail server. The message
inbound to gmail hit, and then took 3 hops through 10.x space
before doing something that generated the bounce.

However, it appears that those 3 inbound 10.x hops weren't in fact gmail space
- there are apparently missing Received: between when GMail received it and
when somebody decided to bounce it (possibly involving a POP/IMAP fetch).
Still unclear who either ate or failed to add the Received: headers.

And it didn't help that the party guilty of the actual bounce, after bouncing
it to the wrong address (mine), turned around and handed the bounce to GMail's
mail servers rather than my site's mail servers, so it *looked* like
GMail was the source of the bounce.

Bottom line: GMail got framed by somebody else's misbehaving mail system.