I was using the Smart Device Management API flawlessly for over a month, then this week.. 1 of 2 thermostats disappeared. (A couple questions on StackOverflow saying "There should be two as I'm setting this up."), but I HAD both of them. Just today when I pinged the API, both thermostats are now gone. My 2 cameras are still on the API device list.
So they were there, now not. The only thing that has changed is I upgraded my Nest account to Nest Aware.. but that shouldn't impact the thermostats' availability in the API?