Is my thermostat defective

Installed a new Ecobee Essentials thermostat today after my old one kept randomly switching to a 60–65° mode without me changing it. Thought the old unit was faulty, but the new one did the same thing on day one! Had to manually override to get back to my scheduled settings. I’ve now turned off Eco+ indefinitely and will monitor if this happens again. Anyone else experienced this? What’s going on here?