My DNS entries went missing after the latest component update of today.
Statically assigned addresses re-appeared after and DHCP and DNS module restart, but to speed things along, I cleared the following DNC leases files.

/var/lib/dhcp/dhcpd.leases
/var/lib/dhcp/dhcpd.leases~

Then restart the DNS & DHCP modules.
Don’t just delete the leases files, rename, or copy them somewhere just in case.