[Evolution] evolution and courier-mta (IMAP): broken messages

[Ángel <angel 16bits net>]

I have been recently attempting to connect evolution to a courier IMAP
server (4.10.0). evolution was unable to show the email contents. The
folders and thread view of available emails (subject, from, date…)
are ok, but clicking one of them doesn't show the body. Inspection of
message source from evolution suggests it got utterly confused,
interpreted some body contents as headers and discarded most of it.

Tested evolution 3.2.3, 3.10.3 and 3.10.4 with all of them exhibiting
this behavior.
On the other hand, thunderbird has no problems retrieving mails from the
same server.

The problem seems specific to multipart messages but I don't know if the
bug lies in courier when providing the parts or in evolution requesting
them.
Both MUAs seem to ask for the emails in different ways and IMAP FETCH
command is not a simple one to grasp.

evolution is using:
A00006 UID FETCH 1:* (RFC822.SIZE RFC822.HEADER FLAGS)
A00008 UID FETCH 1 (BODY.PEEK[])
A00009 UID FETCH 2 (BODY.PEEK[])

getting the full messages on both commands (shouldn't the first one only
reply with the header?)

Even worse, I see the right email in evolution cache despite the wrong
«source».
(I also saw a corrupted version in the cache -before cleaning-, with
paragraphs missing⁈)



Did anyone experience similar problems before? Any suggestion on who to
blame?

I am surprised that there is such bug on either of them. 
But at lest one shall be wrong, as they are not interacting
correctly. :/

I have created a test account with a couple of mails from this list, in
case anyone wants to have a look without setting up the server:

Server: imap.16bits.net
Username: evolution-and-courier 16bits net
Password: bugtest

Best regards