Third NS only gets updates, not full pri -file

I installed ISPConfig on Debian Jessie host and made it as a third name server for a multiserver setup. I set it as mirror of ns1. Now the changes I made do get to ns3, but it does not get the full pri. -file. I have tried stuff, but no luck. The Resync Tool does not offer ns3 or ns2 as alternatives, so that does not help. I read in previous post about copying all the pri files manually, but do I have to do that each time I add this third ns to a zone?
To show the problem, here pri files from ns2 and ns3.

Code:

root@ns2:/etc/bind# cat pri.design.yt
$TTL        86400
@       IN      SOA     ns1.ZZZZZZZZZZ.fi. hostmaster.ZZZZZZZZZZ.fi. (
                        2017052403       ; serial, todays date + todays serial #
                        28800              ; refresh, seconds
                        7200              ; retry, seconds
                        604800              ; expire, seconds
                        86400 )            ; minimum, seconds
;

design.yt. 86400 A        37.59.237.214
foo.design.yt 3600 A        37.59.237.202
ftp.design.yt. 86400      CNAME        design.yt.
www.design.yt. 86400      CNAME        design.yt.
design.yt. 86400      MX    10   posti.ZZZZZZZZZZ.fi.
design.yt. 86400      NS        ns1.ZZZZZZZZZZ.fi.
design.yt. 86400      NS        ns2.ZZZZZZZZZZ.fi.
design.yt. 86400      NS        ns3.ZZZZZZZZZZ.fi.
design.yt. 86400      TXT        "v=spf1 mx ~all"

Code:

root@ns3:/etc/bind# cat pri.design.yt
$TTL        86400
@       IN      SOA     ns1.ZZZZZZZZZZ.fi. hostmaster.ZZZZZZZZZZ.fi. (
                        2017052403       ; serial, todays date + todays serial #
                        28800              ; refresh, seconds
                        7200              ; retry, seconds
                        604800              ; expire, seconds
                        86400 )            ; minimum, seconds
;

foo.design.yt 3600 A        37.59.237.202
design.yt. 86400      NS        ns3.ZZZZZZZZZZ.fi.

So ns3 does get the SOA record with correct serial number, but not the lines that were there before I installed ns3.

If I understood the ISPConfig Manual correctly, I could also add secondary DNS, which looks like then ns3 would be a slave server in BIND9 sense. That I would know how to force to a zone transfer. And this mirror of ns1 and slave can not be used at the same time, I have to choose one way or another. Since ns2 already is mirror of ns1, it seemed easier to make ns3 same way so I do not get two different setups.

I also realised only when debugging this that ns2 is master of the zone, I assumed it would be a slave. I have previously only used bind and set up master and slaves manually. It looks to me this mirroring of ns1 makes it so that ns2 and ns3 do not do bind9 zone transfers at all, there is some ISPConfig magic that syncs the pri files.

 

I did rsync -v -togp pri.* from ns1 to the ns3 /etc/bind -directory. That seems to have broken things, I had to shut down bind9 on ns3 because it answered something wrong and sites stopped working from those hosts that happened to use ns3.
Is it necessary to add things in ISPConfig in some particular order to get the full zone transferred to ns3? I'm thinking the first "zone transfer" went to bit heaven and ISPConfing then sends only changes, so ns3 never gets the full pri-file.
I have tried with three domains, this partial pri file problem happened every time.

 

Forgot to tell versions: ns3 is running ISPConfig 3.1.3 since I installed it on wednesday with latest. Other servers in the multiserver setup are 3.1.2.

 

That was it. I was confused.