Mavlink-router debugging

So… I have one vehicle working that connects at Pixhawk4 running PX4 to a tablet running QGC via a 4g link using the scripts I found here: Peter Burke / 4gUAV · GitLab. I’m using a RasPi Zero W running Raspbian as the companion computer on that vehcile.

Now I want to duplicate it for a second vehicle running the same PX4 software on a Durandal. I made sure the first is off the network, and set up the new vehicle as close to just like the other as I could, except with a RasPi 4 running Ubuntu 22.04 as the companion computer so I can add a bunch of ROS stuff. And for reasons I have not yet been able to figure out, when I connect to the second setup, I get data from the Durandal (i.e. things like orientation and position) but not the parameters nor the mavlink console. I switched hardware and software around to verify that the problem is the mavlink-router running on the RasPi 4… but now I am stuck.

I’ve done my best to match the mavlink-router versions and configuration files, without notable change in behavior. What else should I look at to figure out what is going on?