Are you sure it's not coming back on as it sees a drop in temp so it's calling for heat to avoid a big drop in the room temp?
Mine certainly shuts off radiator valves before the room is at the set temp as the rad will have an amount of latent heat that continues to warm the room for a while after. When the valve sees a drop in temp, it does start the heating even if the temp is above the set temp to avoid the big dip
@Foekie traditional mechanical thermostats switch off when the set point is reached and then wait for the temperature to drop before switching back on. Tado thermostats use PID algorithms that try to predict how much heat is required over a period of time to maintain the set temperature. For example, with an outdoor temperature of 5°C and an indoor temperature of 20°C it may calculate that the boiler needs to be on for 30% of the time. This may result in the thermostat being on when the set point is exceeded, but overall the room temperature should be more consistent than using a dumb on/off thermostat.
If you've recently installed Tado it may take a while for the algorithms to learn how your room heats and cools under different weather conditions.
Many thanks for these answers, the problem is that normally all works well I had the Tado for a few years now something similar happened last winter when I had somebody renting my house the Remeha Avanta 35C kept heating slowly for day's asking 20 Degrees it was 23 degrees in the house while the Central Heating kept on the heating, when I looked it up there was talk a about a 3 way valve sticking, it took 3 day's before an Remeha engineer came and by that time the problem was solved by itself I have never found out what the problem was....... Now today I set the heating from 19 to 22 Degree and went out the house for a while and came back several hours later than anticipated the house now was at 24
Degrees according to the Tado graph the heating should have been turned of an hour before I arrived at the house but looking at the Remeha heater it was still on heating (2 Dots instead of 1) and strangely enough went of 10 mins after I arrived without me doing anything. All very strange, I do not really understand it could it still have to do with the 3 way valve In the Remeha which keeps the heating going. Personally I think it has to do with the Remeha Heater..... really appreciate your feedback :)