Why does DHCPD duplicate reverse zone IP for dynamic update?

Question

ubuntu

In general, the wort is:

DHServ dhcpd: Added reverse map from 15.0.168.192.0.168.192.in-addr.arpa. to laser2PC.suv

and so with any hosts, it updates the direct zone normally.
Moreover, if you clear the list of leased addresses, the
IP address for the reverse zone becomes normal and the update proceeds correctly,
but after a while it again duplicates the IP address.
Why can this happen and where to dig?
The config simplified further nowhere:

server-identifier 192.168.0.1;

ddns-updates on;
ddns-update-style interim;

ddns-ttl 38000;
deny client-updates;
do-rorward-updates;


include "/etc/dhcp/rndc.key";

zone suv. {
       primary 127.0.0.1;
       key rndc-key;
}

zone 0.168.192.in-addr.arpa. {
       primary 127.0.0.1;
       key rndc-key;
}



update-static-leases    on; 
default-lease-time              600;
max-lease-time                  7200;
log-facility			local7;

authoritative;
log-facility local7;

subnet 192.168.0.0 netmask 255.255.255.0 {
  authoritative;
  range 192.168.0.10 192.168.0.254;
  option broadcast-address 192.168.0.255;
  option routers 192.168.0.1;

        option domain-name "suv";
        option domain-name-servers 192.168.0.1;
        option netbios-name-servers 192.168.0.1;
  #ddns-rev-domainname "in-addr.arpa";  # а нам всё равно =((
        ddns-domainname "suv";
        

}

Answer 1

Oops, blunted - somehow I had 2 dhcpd daemons running, one updated the settings, the other did not.