Insteon's empty logbook

I have the Insteon integration connected to a PowerLinc Serial Modem attached via USB with this and have added an On/Off Module. Using the Home Assistant interface, I can control the module on and off. I can see it happen in real life, and the events get added to the logbook.

However, when I physically control the module on or off via the buttons, the events don’t find their way back into Home Assistant. This is a one-direction relationship, where Home Assistant can only control Insteon devices, but cannot listen events it didn’t initiate. Any ideas what’s happening or how I can debug?

After some testing, I’ve come to realize the “Add Device” button only creates a single link, setting the modem as the controller. After manually linking the two devices, Home Assistant was seeing the activity. It’d be nice if the integreation also created a second link with the controller as a responder.

@suderman can you explain your process for setting up both links? I have a new 2413U off ebay, to replace what I believed was a dead PLM.