Wrong Temperature Values showing in Homey Pro

Just as information, because that could affect other apps, too.
Homey uses °C internally as unit for thermostats. If the localization is set to °F, only tbe GUI is converting the temperature to °F. The thermostat itself uses °C.
So every app must use °C to set thermostat capabilities.
So it depends on the app whether it converts to °C or not.