I had some time to do further testing. I changed the reserved IP address for one of these devices and applied the settings which got this in the logs:
May 20 11:12:04 rc_service: httpd 1401:notify_rc restart_dnsmasq
May 20 11:12:05 dnsmasq-dhcp[5748]: not giving name RaspPi4_2GB to the DHCP...