@hard-shovel I had same issue and using older version worked for me too

I tried and tried with my serial gateway, and never got it to function porperly. The serial port was working I could see it and data, but OH3 just refused to recognise the data. After a week, I decided to abandon the serial and flashed a esp8266 attached the nRF to it and bobs my uncle as we say. It goes via MQTT, so takes a little more settting up but works fine. If you want more info I will dig out the pages I used to make it work.

I have an almost identical issue with me ESP MQTT gateway no longer connecting to nodes. Similar issues to start with in that it was good for a number of months then would stop, restart ok, then multiple restarts to begin working. I have now resorted to changing out the 24RF01 module and the ESP to try and locate the issue. Will let you know how I get on.

As this is the outside box, can you post pictures of the inside box controller, I think this is the key to get it on you vera box. I suspect the two buttons actually modulate a high frequency onto the two wires, as you still need to pass audio both ways and power to make it all work.