I would guess no one found a way to control the master thermostat (seems to be wifi but use zigbee to talk to slaves…)? This means you can control the slaves from HA but the main room that has the controller you cannot 
https://www.stelpro.com/en/products/maestro-smart-controller-thermostat-asmc402ad/
Either I scrap the master and buy another slave or have one room not on HA.