Sweet! Yeah, I’m guessing that the iptables-mangle and landing page link setup relies on getting that IP before populating the page, and that it’s not reactive to changing IP address. It might have worked if you were disconnecting networking all together, and joining a different network, but with the wonky way wifi roaming actually works, the mediabox management scripts probably never noticed there was a need to re-trigger.

You’re looking for mdns! Depends on which distro you’re on. For apt based stuff like mint, look for mdns (used to be libnss-mdns on raspberry pies, guessing it’s the same for lint? It’ll install avahi zeroconf stuff if it’s not there already. Check the service is running, then ping $HOSTNAME.local - replace with whatever your host name is.