Difficulty copying messages to nnimap groups

[nathanw@MIT.EDU (Nathan J. Williams)]

I've recently started moving some of my mail from nnml to IMAP
folders, and naturally tried using nnimap to do it. Copying or moving
messages works for most messages, but for some (not all)
more-complicated messages with MIME structure, it hangs. The
*imap-log* looks something like this:

275 UNSELECT
275 OK Completed
276 APPEND "INBOX.cl" {23873}
+ go ahead
... contents of message... where did all these ^M's come from?...
--899389228-1059480176-1173234298=:7884--
... hang

At this point, if I press C-g, Gnus quits doing that and lets me do
other things. If I go into some other IMAP mailbox, the log then gets:

277 SELECT "INBOX"
276 OK [APPENDUID 1173392274 67] Completed
* FLAGS (\Answered \Flagged \Draft \Deleted \Seen $NotJunk JunkRecorded $Junk)
* OK [PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted \Seen $NotJunk JunkRecorded $Junk \*)]  
* 35 EXISTS
* 0 RECENT
* OK [UNSEEN 35]  
* OK [UIDVALIDITY 1173293047]  
* OK [UIDNEXT 225]  
277 OK [READ-WRITE] Completed

... and the message I tried to move is in the IMAP folder (as
seen in another client), but Gnus still has it in nnml, since it
doesn't think it finished the operation.

This seems like a length-mismatch issue of some kind. The original
message file under nnml is:

13 contents-vnder-pressvre:nathanw>ls -l 187
-rw-------   1 nathanw  mit        23368 Mar 10 10:21 187
14 contents-vnder-pressvre:nathanw>wc -l 187
     505 187

And 23368+505 = 23873, the length that was used in the APPEND
command. I'm puzzled why the server seemed to wait for the text of the
277 command to appear before reporting success of 276, but then 277
succeeded (as 277, and not as 77, as I might suspect).

Gnus v5.10.6, Emacs 21.4.1. IMAP server is Cyrus, 2.0.17 (not under my
control to upgrade).

Is this something that is fixed in a later Gnus? I poked around
ChangeLogs and CVS and didn't find anything obvious. Any other ideas?


           - Nathan