To reproduce without need of a printing client, run the command
avahi-browse -a -v -t -r
in a terminal window. Then look for entries arising from CUPS queues. They report "port = [30466]". Entries from IPP printers report correctly "port = [631]" (what CUPS as an IPP-based printing system should do as well).
To reproduce without need of a printing client, run the command
avahi-browse -a -v -t -r
in a terminal window. Then look for entries arising from CUPS queues. They report "port = [30466]". Entries from IPP printers report correctly "port = [631]" (what CUPS as an IPP-based printing system should do as well).