[Samba] Bad zone problem after join, seize, demote

[Taner Tas]

I'm testing to a seamless upgrade from 4.3.11 to 4.8.3 on my test setup. 
Database migrating from 4.3.11 was successful. After "samba-tool 
dbdcheck --cross-ncs --fix --yes", 4.8.3 was launching ok except 
replication (4.3.11 to 4.8.3 : WERR_BADFILE). After demoting older ones 
and seize (transfer doesn't work) all roles to 4.8.3, dns (bind_dlz) 
service won't start anymore due to the bad zone error.

Before demoting and stopping services (samba and bind) on 4.3 DC's, 
samba_dnsupdate and dns service was working on new 4.8.3.

I have 10+ subdomains with reverse dns records. These zones were 
probably added using RSAT DNS tool in the past. If I did something wrong 
during join & demote, it would be nice to know if I have any option 
except deleting/re-adding all subdomain dns records in order to make dns 
service work again.

Jul 24 08:19:21 dc4 named[1526]: loading configuration from '/etc/bind 
/named.conf'
Jul 24 08:19:21 dc4 named[1526]: reading built-in trusted keys from file 
'/etc/bind/bind.keys'
Jul 24 08:19:21 dc4 named[1526]: using default UDP/IPv4 port range: 
[32768, 60999]
Jul 24 08:19:21 dc4 named[1526]: using default UDP/IPv6 port range: 
[32768, 60999]
Jul 24 08:19:21 dc4 named[1526]: listening on IPv6 interfaces, port 53
Jul 24 08:19:21 dc4 named[1526]: listening on IPv4 interface lo, 
127.0.0.1#53
Jul 24 08:19:21 dc4 named[1526]: listening on IPv4 interface enp0s3, 
10.220.1.22#53
Jul 24 08:19:21 dc4 named[1526]: listening on IPv4 interface enp0s8, 
10.0.2.22#53
Jul 24 08:19:21 dc4 named[1526]: generating session key for dynamic DNS
Jul 24 08:19:21 dc4 named[1526]: sizing zone task pool based on 5 zones
Jul 24 08:19:21 dc4 named[1526]: Loading 'AD DNS Zone' using driver dlopen
Jul 24 08:19:21 dc4 named[1526]: samba_dlz: started for DN 
DC=testdomain,DC=org,DC=tr
Jul 24 08:19:21 dc4 named[1526]: samba_dlz: starting configure
Jul 24 08:19:21 dc4 named[1526]: zone 0.210.10.in-addr.arpa/NONE: has no 
NS records
Jul 24 08:19:21 dc4 named[1526]: samba_dlz: Failed to configure zone 
'0.210.10.in-addr.arpa'
Jul 24 08:19:21 dc4 named[1526]: loading configuration: bad zone
Jul 24 08:19:21 dc4 named[1526]: exiting (due to fatal
Jul 24 08:19:21 dc4 systemd[1]: bind9.service: Main process exited, 
code=exited, status=1/FAILURE

Thanks.