Wow... you weren't kidding about the turnaround time. Fix will be going into next beta release. +1 for Domoticz...

Erp... strike that. Looks like the MySensors nodes are working just fine. It's the interface to Home Assistant that seems to be buggy. I found the MYSController app to monitor the gateway directly, and I can see everything coming through from my sensors, serial connection or no. So, case closed here, but the search for the best controller to pair with my MySensors network goes on...