If I understand you correctly this is an issue in your heating cq the Spirit Valves that even when it is off it opens the heating and even when it reaches more then the 16 degree it still keeps the heating open.
I once noticed that my valves were in an ‘off state’ and did not accept commands but remained in the set temp position. I resolved that by sending some test flows to them, changing the temperature and putting them in the ‘comfortable’ state.
As @Dijker also says, I think this is not a Homey issue, but heating / valves issue.
Can you confirm that if you change them manually that you can see the new setting in homey? My point is, can the valves reach homey?
I resolved my connectivity issues by installing a few smart plugs in my house. Homey’s antennas are pretty bad and by installing one smart plug near homey, which automatically started serving as a zwave router solved all of my issues. I am a very happy Spirit valve user