Actually, it looks like the following is not matching
the 'From foo(_at_)bar' message produced by 'formail' when it
notices a duplicate message id while processing the -D
# if the message id is duplicated, formail passes in an
# empty email body, with a 1 line "From foo(_at_)bar'. This
# is a bug, I think - the workaround is to check, and
# just dump the message. Hoever, this won't work well
# for mal-formed mail boxes.
* ^From foo(_at_)bar
The message consists of one line only, the 'From foo(_at_)bar ...' line.
There is no blank line seperating the header from the body, and
there is no body. Is procmail able to match the 'From ' lines?
Is the fact that the mail message is not well formed causing the
match to fail?