Use the command register-dnsclient in PowerShell or ipconfig /registerdns on the CMD to get the Windows client to register itself (or try to) in the appropriate DNS server. It will use its current DNS server to establish where the authoritative server for the zone is (zone will be whatever is set on the computer (e.g. computerhostname.mycorporationdomain.local).

Do not change the MNAME of a zone (SOA) to point away from the primary server if you want DDNS updates to work on it. If you point the MNAME at a secondary, dynmaic clients will try to update the secondary which will fail (as it is read only).