I'm getting an unexpected payload output when asking Google to turn ON the Thermostat node, or in my case an air conditioner. Instead of the payload.mode showing as "on" it's shows as "cool". I think it must be an error because "on" is a supported mode. The voice output from my Google Home is "Ok changing the air conditioner to cool".
Please don't post in two places. Since you solved your issue with the other thread, please mark this solved.