This is great news! Even if it is not a perfect, permanent fix, it seems we are in much better shape. Thank you so very much for taking so much of your time to troubleshoot and help come up with this working solution @J-N-K!
I was going to say, even though “LastVoiceCommand” wasn’t working, the data still was there, in the API. If you follow the link (updated of course with your own, local IP address and account key) that was provided in the Preview and Beta version of the Add-In, under the section:
"Advanced Feature Technically Experienced Users" http://openhab:8080/amazonechocontrol/account1/PROXY/api/activities?startTime=&size=50&offset=1
…you will still see your “LastVoiceCommand” data is present there in the API. I am not very proficient with coding, especially this type of coding, but I was thinking maybe Amazon had renamed a variable or changed a header or there was a cookie problem or something and maybe if you look at the API through this link that we could figure out what changed. But now it seems we are in good shape!.