Hello Henkjan!
Eve, and all other 3rd party HomeKit-apps (Home.app is the only privileged one) are only clients using the HomeKit framework and its (public) capabilities. So a change in temperature or target temperature should be visible and updated in all HomeKit enabled apps at least upon opening the app where the sensors are all queried.
I don't know why Home does not show the actual data, sorry. Best regards, Volker
Oct 20, 2020