[Dovecot] pine - preauthenticated IMAP - mbox.gz

Hi,

pine - preauthenticated IMAP - mbox: OK
pine - preauthenticated IMAP - mbox.gz: FAIL
SeaMonkey - IMAP - mbox: OK
SeaMonkey - IMAP - mbox.gz: OK

( More details: 

http://dovecot.org/pipermail/dovecot/2009-February/037665.html )

What could be the problem? Misconfiguration, pine bug, dovecot bug?

Thanks, Nil.