[Dovecot] test77, yahoo & fetchmail

I've run into a rather narrowly scoped problem ..

On test77 and test78, mails from Yahoo's webmail are seen, by fetchmail using imaps, to have a 0-length body. When fetching, it claims "0 body octets". Other mail clients (mutt, kmail) can view the messages fine. pop3s retrieval works as well. Every other email I've received so far works fine. It's just those sent by Yahoo's webmail service that have the problem. imaps retrieval does, however, work fine with test76.

Let me know if there's anything I can do to help track this down.

Thanks, Chris