Table not cleaning up drom dead tuples

Good day. It seems that we have some strange case of VACUUM malfunction and
table bloating.

PostgreSQL 9.5.3
OS #uname -a
FreeBSD db-host 10.2-RELEASE-p18 FreeBSD 10.2-RELEASE-p18 #0: Sat May 28
08:53:43 UTC 2016
root(at)amd64-builder(dot)daemonology(dot)net:/usr/obj/usr/src/sys/GENERIC
amd64

General info about our database:
https://gist.github.com/aCLr/dec78ab031749e517550ac11f8233f70

Information about problematic tables:
https://gist.github.com/tarabanton/edf7f8dc26eb7ec37a9cfa3424493871

As you can see, there 2 to 10 times dead tuples compared to actual row
count.
We've tried VACUUM FULL and CLUSTER without any success.
There is no long term locks, idle in transaction requests or prepared
transactions.

We are temporarily fixing this like that:
BEGIN;
CREATE TABLE _orders_temp (LIKE orders_y2017_m3 INCLUDING DEFAULTS
INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING COMMENTS);
INSERT INTO _orders_temp select * from orders_y2017_m3;
ALTER TABLE orders_y2017_m3 RENAME TO __orders_y2017_m3_to_drop;
ALTER TABLE __orders_y2017_m3_to_drop NO INHERIT orders;
ALTER TABLE _orders_temp RENAME TO orders_y2017_m3;
ALTER TABLE orders_y2017_m3 INHERIT orders;
COMMIT;

but bloat returns again and again
--
___________________________
С наилучшими пожеланиями,
Антон Тарабрин

With best regards,
Anton Tарабрин