Running monitor dhcp on a productuon router I see no DHCP related messaged, even when there is a lot of traffic accourding to tcpdump:
vyos@vyos:~$ monitor dhcp
08:46:14.359844 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:50:56:80:02:ba, length 300 08:46:15.360480 IP 192.168.189.2.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 300