We have our 2 server Server 2008 spit-scope DHCP configured to register DNS using a domain user account. This generally works except for when a DHCP client renews its DHCP lease from the other server, gets a new IP from the the other server's lease range and the DNS doesn't get updated to reflect the new IP because the old host entry is already there. The old entry doesn't get removed until scavenging time or manual deletion.
Sometimes to get around this issue, we manually delete the host entries from DNS and then run ipconfig /registerdns on the client and then ipconfig /flushdns on the system trying to access the client.
This has been working OK until recently. Now we have a new problem of multiple clients failing to register DNS themselves.
Windows System event logs on several different clients have errors that say the name could not be registered on the interface because another computer would not allow the name to claimed by the computer.