I just looked at the dates a little more closely.  For runq to remove the mail
the same day that it was delivered implies that it thought that the mail
was successfully delivered (or that the clock on the file server is 3 days
off).

The fact that the message was removed without an accompanying smtp.fail message
with the same timestamp implies that the smtp succeeded.  However, there should
have been a log entry in smtp should that have been true.  Your original
message shows:

#
#	Looking /sys/log/smtp we can confirm these two mails have not been delivered
#
term% tail smtp
...
term%

I'm not sure what this means, but I'm assuming it means that there was
nothing in the smtp log?  This is all just a bit wierd.  Have you changed
the /mail/lib/remotemail script?  It really looks like the script did not
return an error code as if the smtp had succeeded.

If there is inded nothing in /mail/lib/smtp, it sounds like either the
remotemail script is broken or smtp is.  Either way, I think you need to
start debugging.