I've had the same Nest thermostat installed in my apartment for a few years now and honestly, I've loved it.
Within the past couple months, however, the thermostat would get stuck running forever; seemingly at random. It didn't matter whether it was set to heating or cooling, the only way I knew to stop it was to basically shut off the HVAC entirely and leave it sit like that for hours. Rebooting the thermostat did nothing.
Today it happened for the third time. This time I just so happened to be trying to turn the heat off via the Nest app on my Android phone. Both the Nest app and the display of the physical Nest thermostat itself reported the heat was off-- and yet the HVAC was still running. Again I started fiddling with the thermostat settings both from the physical device and from the Nest app, but to no avail. On a whim, I decided to check the Nest app settings on my Android phone(Settings -> Apps-> Nest). I noticed "Remove permissions if app is unused" was enabled by default.
I disabled this setting, and immediately my HVAC shut off like it was supposed to.
It seems that somehow when my phone removed the app's permissions without me noticing it, it would sometimes get the thermostat into this bizarre state where the thermostat's display would update but it would not stop it's last operation.
