I have asked a question:
What happens to the sketch / memory when Arduino is powered off?
In one comment a likely solution was found (DS18B20 returns 85 deg C after power up), which mostly turns the question moot. The question did not contain enough details (it did not mention at all DS18B20), it was "loaded" with my assumption the issue is with the Arduino memory.
I am not sure what to do with the question now. Should I delete it completely, or is there some way to salvage it - to edit it so that it contains enough detail so that the solution related to DS18B20 is more apparent? Or should I keep it, as it is, as even in current form it is not that bad, and ask a new question about DS18B20 after reset behaviour?