Just in time for winter...
Something seems to have broken with geofencing, auto-away, and multiples devices. Please take a look at the Reddit thread about this because many others are also experiencing it. My Nests never go into eco/away mode even when all users and their phones are away from the house. This option is mostly what saves me money on my utilities, but it stopped working.
MarcusAureliusSeneca about
Nest, v5.9.2