Multiple valves and manual decreasing behavior

I would like to verify that this is the intended correct behaviour, as it seems to me it is not and I do not like it much.

First let me explain. I have two houses with Netatmo products. In first of them I have one relay+thermostat and one radiator valve. I am using "economy priority" settings (sorry if it is not exact translation, i have it in Czech in the app), not "comfort priority". That means that valves with high temperature settings not yet reaching that temperature are not enabling central heating in normal program mode, that is directed only by main thermostat. That is fine.

Now if heating is currently off (as main thermostat reached desired temperature) and I increase the temperature setting on the valve manually temporarily for let's say 15 minutes period, then heating is turned on in the whole house, because when you change valve temperature manually, it still triggers the main heating even in "economy" mode. Only for period when this manual override is in place. I understand that, that is fine for me.

What seems to be wrong is my second house, where the configuration is similar, only I have 4 valves. Now let's say all valves are set to 25 degrees so they are turned on. Main thermostat is set to 21 degrees of desired temperature and there is currently 22 degrees in the house so the heating is currently off. Fine. Now I manually DECREASE temperature setting on one valve to 18 degrees in order to turn it off (for example in case heating will be turned on later and I want this radiator to be disabled for some longer time for any reason). I would expect the radiator valve to be turned off immediately and that happens. And I would expect nothing else. But what happens also is that thermostat goes to "controlled by valve" mode and heating starts in the house, which is bad. I expect this is because the system finds out something like "hey, some valve is in manual mode" (the one I turned off) and also "hey, some valve is not on its maximum" (but those are in automatic mode) and so heating is turned on. I think this is bad behaviour, that this is a bug. Am I correct? Can that be somehow influenced? Thanks.