Wireless reciever calling for heat when no devices are on. Gas bill is astronomical!

I have 6 radiators with Smart TRVs, one room thermostat and two radiators with manual TRVs.

In theory, the only way my boiler should turn on is if one of those Tado devices calls for heat, right? It should be impossible for the manual TRVs to activate the boiler.

However, I have seen multiple instances of the boiler switching on when all Tado devices are off. It heats the two manually controlled radiators since those valves are the only ones open.

My gas bill last month was crazy. It has clearly been heating these two rooms a lot and has eaten up any saving I could possibly hope to make.

Have I misunderstood the way the system works? Could these manual valves be triggering the boiler?