We’ve been having a lot of issues recently with Windows 10 devices not updating DNS properly when DHCP servers are set to do the dynamic updating on behalf of the client.
There a LOT of advice out there- adding servers to the builtin DNSUpdateProxy group, fiddling about with netsh etc. The long and the short of it from my perspective is don’t waste time with these as I couldn’t get them to work, just switch off dynamic updating on the DHCP server and let clients register themselves.
Whatever the actual issue, this seems to be new to Windows 10 and although it could well be related to having an older domain functional level etc, this isn’t something I can fix easily because most DCs are still on 2008R2 and they’re spread across a wide geographical area so I can’t just upgrade them. Changing the way DNS is updated seems to have fixed the problem so that’s fine with me, and is a much faster solution than systematically trying the myriad suggestions out there.