The MINTEMP setting sets the measurement below which it thinks your sensor is broken. You could set MINTEMP below the last entry in your thermistortables.h to make it never trigger.
Many of the thermistor tables in Marlin don't go past zero. If your lab is -10°C, then you should make sure the thermistor tables you are using go below the expected environment, and set MINTEMP appropriately.
You could add a {1023*OVERSAMPLENR, -273} line to [
github.com] and set MINTEMP to -20 or so, or you could measure the volts at a few relevant temps and put in a few {1023*volts*OVERSAMPLENR/5, temperature } entries in there.