[Dovecot] Sieve problems (not matching emails expected to match)

I have a sieve file that reads like this:

require "fileinto";

# Emacs if header :contains "List-Id" "emacs-devel.gnu.org" { fileinto "mail.emacs-devel"; } elsif header :contains "List-Id" "emacs-bidi.gnu.org" { fileinto "mail.emacs-bidi"; } ...

Unfortunately the List-Id based lines don't appear to be working, although some other ones do. The attached test message does not get delivered to the mail.emacs-devel list. Why?

-- Michael Welsh Duggan (md5i@md5i.com)