New Condo with ST302NP thermostat

New Condo with ST302NP thermostat
Regularly, the probe begins to measure a falling temperature ... falling ... constantly ...
It is necessary to recalibrate supposedly, I do not see the relation with the measurement probe.
We recalibrate however.
The next day the probe measures a temperature which drops endlessly again
The radiators are running full blast! It's been 4 times in 3 weeks. This summer we will have to cut the power I imagine?
And when we reset, the measurement becomes normal again, we go from 2 to 24 !!! Thermal shock !!!
Never seen this, reset needed almost every day.
Replacement by MYSA thermostats that I recommend. It works much better!