I'm a bit confused about your "DHCP static" and "DHCP4 Lease".... do you have static mappings for some server instances, but others getting DHCP addresses from a pool and specifying their own preferred hostname? or...?
What is your system Domain Name? (System -> Settings -> General -> Domain Name)
# nslookup opnsense.domain.com 192.168.40.1Server: 192.168.40.1Address: 192.168.40.1#53Name: opnsense.domain.comAddress: 192.168.100.1Name: opnsense.domain.comAddress: 192.168.20.1Name: opnsense.domain.comAddress: 192.168.40.1Name: opnsense.domain.comAddress: 192.168.1.1Name: opnsense.domain.comAddress: 192.168.1.250Name: opnsense.domain.comAddress: 192.168.10.1Name: opnsense.domain.comAddress: 192.168.30.1
What is the Domain Name for the DHCP service? (Services -> ISC DHCPv4 -> [interface] -> Domain Name)
What is the Domain Name for the Static Mappings? (it's an optional setting for each one)