I don't understand how this would mean that IP addresses of these domain controllers would change. They are new domain controllers with new names and IP addresses and are automatically added to Active Directory-Integrated DNS Zones.
It is possible to change an IP address of a DC, but usually this is only needed if it moves to a different site and the subnet changes. If you do so, these applies:
If you change the static IP address of a domain controller, make sure
that the IP address is included in the respective Dynamic Host
Configuration Protocol (DHCP) scope.
You must also verify that DNS resource records are updated on the DNS
server that the domain controller references as the preferred DNS
server in TCP/IP settings. In DNS, verify the values of the following
resource records. If they have not updated automatically, update the
IP address in these resource records:
The answer is that all probably changes automatically as designed, but as a responsible systems administrator you should always verify that everything is as desired and fix if necessary.
The DHCP scope is where you set the new DNS server IP addresses to all client computers. Restarting switches would be the fastest way to force all DHCP clients to get the new settings immediately.