Hello I’m the guy working on the new binding version.
I would definitely agree with @rlkoshak and @rossko57: go with the stable binding for now. The alpha binding is, well, alpha and at this stage for users who are willing to experiment the new binding and are experienced with openHAB and troubleshooting bindings in general. At this stage errors are expected for sure.
Actually you are using a feature (data thing) that I have not yet documented on the thread since it’s still unstable. The only document for the alpha exists in the form of examples on that thread.
Best,
Sami