Uncheck DHCP registration does not clear entries
Uncheck the DHCP registration box in Unbound setting GUI should clear the contents of /var/unbound/dhcpleases_entries.conf to stop resolving these hostnames. Uncheck static entries should also update host_entries.conf. The current behavior is that these files leave untouched and unbound continue to resolve these hostnames.
@Gertjan has provided a fix, would like to see this ported into official release: