dovecot - Nov 2015 - [dovceot-2.2.19] doveadm fetch with fts_squat returns random results

Hi all!

I've got problem with results returned by doveadm fetch. The are random
and incorrect. I'll try show you:
- trying to fetch emails with both: nonexistent header name and non
existent value of header name:
-- doveadm fetch -u user at domain uid HEADER X-Sasdasdsendasasdasdasdasaer
XXtuxie |grep -c uid
0

- trying to fetch email with: non existent header name and existent
value of header (value exists usually in header X-Sender)
-- # doveadm fetch -u user at domain uid HEADER
X-Sasdasdsendasasdasdasdasaer tuxie |grep -c uid
13743
second search:
-- # doveadm fetch -u user at domain uid HEADER
X-Sasdasdsendasasdasdasdasaer tuxie |grep -c uid
16639
another search with the same criteria:
-- doveadm fetch -u user at domain uid HEADER X-Sasdasdsendasasdasdasdasaer
tuxie |grep -c uid
20296

so the number of fetched emails is random and none of them contains such
header:
-- # doveadm fetch -u user at domain hdr HEADER
X-Sasdasdsendasasdasdasdasaer tuxie |grep -c X-Sasdasdsendasasdasdasdasaer
0

- now I'm searching for email with existent header contained existent value:
-- # doveadm fetch -u user at domain uid HEADER X-Sender tuxie |grep -c uid
50699
second search:
-- # doveadm fetch -u user at domain uid HEADER X-Sender tuxie |grep -c uid
50375


It looks for me that searching is done only for value of header not for
both header name with given value.
Next I turn off fts_squat in config and now results are correct. If
someone uses doevadm expunge with fts_squat should be carefull.
I just tried fts_lucene - no problem.

Regards,
Marcin