exim+dovecot+sieve issue

[JM]

Hi,

We have mail server in production, with Exim + Dovecot + Mailman + OpenLDAP
+ Roundcube webmail server.
Openldap keeps mail accounts in db, exim uses lmtp transport to deliver
messages to dovecot.
Mailman is responsible for mailing lists, Roundcube webmail has managsieve
module to create sieve filters.

Exim router,transport for dovecot

> localuser:
>   driver = accept
>   domains = +local_domains : +virt_domains
>   check_local_user
>   transport = dovecot_lmtp
>   cannot_route_message = Unknown account
>   no_more


> dovecot_lmtp:
>   driver = lmtp
>   socket = /var/spool/dovecot/lmtp
>   batch_max = 500
>   rcpt_include_affixes


It worked perfectly, but after upgrade from Dovecot 2.2 to Dovecot 2.3
major version, I've found a lot of strange errors in exim panic.log

> mail exim[7821]  Failed to get user name for uid 1175
> mail exim[7880]: Failed to get user name for uid 1173

etc
where uids are ldap accounts and recognized by system (id 1175 shows user's
name and group)

Even worse, some clients start to receive notify email with strange
content, when sending email to mailing lists

>  user at domain.com
>     Delay reason: error in redirect data: malformed address:
>     someuser1 at domain.com may not follow someuser2 at domain.com  in "
> someuser3 at domain.com ..some crap here.." , where someuser addresses are
> not related to recipient address and unknown for sender.


After some investigation,I've found out that dovecot's sieve produces these
errors (I suspect sieve vacation, when user creates vacation via Roundcube
webmail).
If set "submission_host = exim ip" in dovecot.conf, exim doesn't produce
errors in panic.log anymore, but clients still receive email with malformed
address.
Please help me to find the root of the problem (some broken sieve filter in
user's maildir, misconfiguration or breaking changes in new Dovecot
version?)

Current software
Gentoo  with 4.14.90 kernel
Dovecot-2.3.7.1
Exim-4.92.1
Mailman 2.1.29
Openldap-2.4.47
Roundcube-1.3.8

Dovecot.conf attached

Regards,
Juri
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