[Samba] New PTR records not visible

[miguel medalha]

I just joined two new DCs to a domain. I created new PTR records for them
like this:

samba-tool dns add dc1.mydomain.com  10.168.192.in-addr.arpa 8 PTR
newdc.mydomain.com
Record added successfully

samba-tool dns query adiafa 10.168.192.in-addr.arpa @ PTR
Name=8, Records=1, Children=0
    PTR: newdc.mydomain.com (flags=f0, serial=162, ttl=900)

nslookup 192.168.10.8
** server can't find 8.10.168.192.in-addr.arpa: NXDOMAIN

The same happens with the other DC and with a new Samba domain member.
However, with other servers whose PTR records were added from Windows RSAT:

nslookup 192.168.10.1
1.10.168.192.in-addr.arpa   name = someserver.mydomain.com

Does anyone know what's going on?

I am using the Samba internal DNS server.