Microsoft Active Directory and DNS on Multiple Sites

Solution 1:

DNS by default will return round-robin entries. This has nothing to do with how a Windows client natively locates a domain controller.

DNS will also return a local address if Netmask Ordering is enabled (default), and the client and DC are on the same 255.255.255.0 subnet. If Netmask Ordering is not applicable, you can use DNS policies to influence what records are returned for each location.

Finally, if you have DC's registering for the domain's same as parent record, and they aren't globally accessible, that is what should be fixed. DNS Mnemonics can be used to fix that.

https://dirteam.com/paul/2013/01/02/preventing-spoke-dc-s-from-advertising-in-the-hub-site-for-authentication-availability/