Thanks for the step-by-step, it helps break down what’s going on internally. The gist of it is there’s some saved state that is not exposed to the user.
Both channels (1 and 2) have a programmable amplifier at their input. Presently whatever amplifier setting is loaded when the channel input is switched to the temperature sensor is kept, so if the amplifier setting was too high the meter will say the temperature is “OVERLOAD”.
Regarding the temp reading of -271 or 0x000000 – I am not sure where that’s coming from. You’re right, these behaviors should be considered bugs, so I added this as an issue on the Android App Github page. Will try to get it sorted soon.