Sort by date wierdness

[Chris St. Pierre]

I have a user whose inbox has a few messages that are sorted
incorrectly.  We first noticed this using IMP (part of Horde), which
uses IMAP to do its sorting.  The user's inbox lists the following
messages, in this order:

2446	 09:54:04 AM ...
224	 02/21/2002	...
339	 12/31/1903	...
2445	 06:32:26 AM ...

Cyrus reports the same dates:

* 2446 FETCH (INTERNALDATE "24-Aug-2006 09:55:30 -0500")
* 224 FETCH (INTERNALDATE "20-Aug-2006 09:32:03 -0500")
* 339 FETCH (INTERNALDATE "20-Aug-2006 09:32:04 -0500")
* 2445 FETCH (INTERNALDATE "24-Aug-2006 06:32:34 -0500")

As you can see, messages 2445 and 2446 are sorted correctly, but the
others both have INTERNALDATEs of several days ago, when we migrated to
Cyrus -- they don't have INTERNALDATEs between 6:32 am and 9:55 am
today.

I turned on telemetry logs for the user and checked her email. IMP
issues the following command:

UID SORT (REVERSE DATE) US-ASCII ALL

The response starts:

* SORT 2727 2726 2725 2728 2724 2723 2720 224 339 2698 2697

As you can see, the user has received some mail between the time I did
my initial debugging, and messages #224 and #339 have actually moved
*up* the list.  This morning, they continued to move up the list and
are now nearly the newest messages in the inbox when sorted by reverse
date.

My Cyrus IMAP version is the latest offered with RHEL 4:

% rpm -qi cyrus-imapd
Name        : cyrus-imapd                  Relocations: (not relocatable)
Version     : 2.2.12                            Vendor: Red Hat, Inc.
Release     : 3.RHEL4.1                     Build Date: Sat 23 Apr 2005 03:45:01 PM CDT

Any ideas what might be causing this?  Thanks!

Chris St. Pierre
Unix Systems Administrator
Nebraska Wesleyan University