Unread Mail flag being reset frequently with dovecot -git master-2.2

[Reuben Farrelly]

Hi again,

I'm experiencing problems with the Dovecot git master-2.2 branch, in 
which mails that have been previously read are randomly appearing as 
unread.  This happens slowly and affects more and more emails the more 
changes that occur to a mailbox.

I am using Maildir format and on Gentoo Linux x86_64 on local disks.

Usually only a few at a time change their status - and it seems to be 
random which ones lose their read status.  Typically though they are the 
most recent emails that have been delivered in the past few months (I 
haven't yet seen this occur with any really old emails).

This problem is MUA independent, it can be observed with Thunderbird as 
well as Roundcube.  If I go in and mark all mails as read then they will 
show as read for a short while until they too slowly start become 
'unread' again.

Currently I'm running git rev from 
https://github.com/dovecot/core/commits/master-2.2 :

f292589f4b85e02d97d974dfe34324c6c0bb9d9f   (I can't run anything newer 
due to an SSL symbol error which I reported earlier).

This rev:

b1254dfe442639236f881afae85e0739520ab409

Is known to be good, so the problem started happening somewhere between 
these two.  (I know there are a lot of in-between revisions, but 
bisecting that could take days of time).

Dovecot config is up at:

  http://www.reub.net/files/dovecot/thunderstorm-dovecot.conf

Rawlog debug files are at

  http://www.reub.net/files/dovecot/rawlogs/

Hopefully someone else may have seen this happen before.  Are there any 
other debugs I can gather which will help get to the bottom of this?

Reuben