Hey! So sorry that happened I will send this feedback to the app team. Just to make sure I have it right once the low water alarm went off your timer which you had started before reset and then your device was no longer reading the correct temperature?
The incorrect temp readings sound slike it may have been from steam getting into the head of your unit. Was your bath covered? If so, make sure there is a small hole for steam to escape away from the head of the unit.
Let your device try out in a bag of rice, this should absorb any extra moisture.
Let me know if that helps or if you need anything else!