Solved! (with workaround)
Its actually the combination with the new entity for zigbee SONOFF TRVZB “number…local_temperatur_offset” in the device configuration and the template Advanced Heating Control
Workaround is: deactivating the automation from the template Advanced Heating Control with the thermostat. I needed to reset the thermostat to factory defaults, but do not have to re-register in the zigbee network.
Then deactivating the entity of local_temperatur_offset in the device settings and upgrade the template to beta version 4. Here I have to activate the “Generic Calibration” and “Calibration Full Rounding”.
The issue was that the automation tried to set the offset temperature from external thermometer in the thermostat. Then the actual temperature is just jumping from the thermostat.