So what we are pretty sure we have narrowed it down to is a WiFi device that reports the temperature of the refrigerator to an online portal that sends out notifications when there is an out of range event.

There is an inside the fridge sensor and that sends the information to a receiver outside the fridge. The receiver part is what has the WiFi built in. I think the inside sensor to outside receiver communicate using 900 Mhz.

Who would have thought to check the refrigerator?