Not sure when this began to happen but the hl7 protocol isn't detected unless it's being sent on port 2575 (iana registered port). This is happening on Windows and *nix. I have previously (in 2019 is when I can last verify it) been able to sniff HL7 traffic regardless of which port is being used. is this something to do with the dissector or is there a setting in Wireshark that needs applying?