This behavior can occur if there is no reverse lookup zone for the IP subnet, or if the reverse lookup zone is not configured to allow dynamic updates.
Since there is no dynamic reverse lookup zone, the registration fails, but the DHCP database cleanup, performed every 60 minutes, attempts the registrations that previously failed.
If the client has moved to a new IP subnet, the the A record is registered using the old IP address.
To resolve this issue, create a reverse lookup zone for the subnet that hosts the client computer in DNS.
It's not just for resolving IP addresses into names and vice versa.