Unable to change nest thermostat temperature through automation or scene

I'm trying to set up an automation or scene through Homekit to adjust the temperatue on my Google Nest thermostat so that when I leave home or arrive home, it changes the thermostat accordingly. In Homekit, when the automation or scene is invoked, the temperatue displayed in the Homekit app changes for an instant, then it goes back to the previous temperature. I've tried it numerous times with the same results. I'm able to adjust the temp manually and it sticks, but not so when done in a scene or automation. I've removed and re-aded the scene and/or automation several times.

Any ideas/suggestions are appreciated.