chwala plugin in multi domain config

[Rand Druid]

I setup 3 domains in Kolab 3.1. After some fighting with configs, I can
normally login to all 3 domains with roundcube. All works strictly over
https.

But "chwala" plugin works only in one domain (and not in first). In others
page is empty.
I found suspicious entries in "/var/log/chwala/sql"

"good" domain:
[12-Feb-2014 07:19:20,000000 +0100]: [1] SELECT vars, ip, changed, now() AS
ts FROM session WHERE sess_id = 't4n1am6lfao695sc6h35gldp33';
[12-Feb-2014 07:19:20,000000 +0100]: [2] DELETE FROM session WHERE sess_id =
't4n1am6lfao695sc6h35gldp33';
[12-Feb-2014 07:19:20,000000 +0100]: [3] SELECT * FROM users WHERE mail_host
= 'localhost' AND username = 'name.surname at example.com';
[12-Feb-2014 07:19:20,000000 +0100]: [4] DELETE FROM cache WHERE user_id =
'8' AND cache_key LIKE 'IMAP.mailboxes%';
[12-Feb-2014 07:19:20,000000 +0100]: [5] INSERT INTO session (sess_id, vars,
ip, created, changed) VALUES ('qjnncuj7dpp1d08j8kbt4hav96', '....cuted
out...', '192.168.88.175', now(), now());

"faulty" domain:
[12-Feb-2014 07:13:21,000000 +0100]: [1] SELECT vars, ip, changed, now() AS
ts FROM session WHERE sess_id = 'null';
[12-Feb-2014 07:13:21,000000 +0100]: [2] DELETE FROM session WHERE sess_id =
'null';
[12-Feb-2014 07:13:21,000000 +0100]: [3] INSERT INTO session (sess_id, vars,
ip, created, changed) VALUES ('null', '', '192.168.9.2', now(), now());

2 strange things:
1) sess_id = 'null'
2) in first case, in INSERT statement IP address of server, in "faulty"
case, IP address of my (=client) pc is used

Any ideas?

P.S. External access to /chwala/ not working for all domains, with "Internal
system error!". Didn't check this issue yet...