I have HA set up with multiple interfaces (VLANs.) Most everything works except for Matter commissioning. I have MDNS reflection enabled on my router (UniFi) including my user network and both IoT networks (isolated-iot, cloud-iot).
Thread is working fine from HA. I have both Matter and Homekit thread devices talking to my HA OTBR and they are working great. The problem is that OTBR _meshcop._udp advertisements are not showing up on my home VLAN. I can see OTBR advertisements from all of my HomePods and an Aqara hub, but not the HA OTBR. So this means when I go to add a new thread device, I get an error: "Failed to save thread network credential, error: Thread network credentials does not match with any of the active thread networks around"
So even though Thread is working, my phone can't see the HA OTBR.
I suspect the answer might be to set the "Backbone Network Interface" which has the note "The network interface used for the backbone network. If not specified, it falls back to the primary interface."
Still, even if OTBR used the wrong interface, MDNS adverts should still be showing up because of MDNS reflection.
Anyway, other MDNS services are working between HA and the various VLANs. For example, all of my HA HomeKit hubs show up. This is why I think it's a problem with the OTBR "app" rather than with HA. Any help would be appreciated.