Upon closer examination of the log, it looks like the $@ argument string is empty for many of those messages. But some others are routed back to sendmail with the .procmail extension added at the end, which should result in their being forwarded to the correct recipient. Is that correct? Again, check Sendmail's logs. Perhaps also add a condition to Procmail to save to a temporary location if $@ is empty.
Code:
ARGS="$@"
:0:
* ARGS ?? ^^$$
temporaryfile.emptyargs
You could add that before the final :0w recipe. Any messages which are saved in the temporaryfile.emptyargs mailbox are basically errors, but perhaps you can diagnose the problem from that.
Referring to the page where you got this set-up, can you verify that you indeed have tabs in the right places in your
sendmail.cf file?
Sorry for the late reply, I had forgotten this page open in a browser tab so the site thought I had already seen your response /-:
