CT100 Spontaneously Changed to AC Mode

This morning, my CT100 thermostat suddenly went to Cool (AC) mode. Nobody touched it or the app. It shows in the Events List as the thermostatMode changing, but I don’t see anything that would have triggered it. It’s hooked up to Alexa and IFTTT, but I don’t see any record of them changing it. Some apps can use it (such I’m Back and Goodnight) but none that should change the mode.

Anyone know if there’s a way to tell if SmartThings changed it, or if it changed on it’s own and just reported that to SmartThings?

Pretty disturbing - if this happened while we were out of town we could have some water damage.