I you look at the Parent device, States shows several items but one is:
- deviceSetting : {0={HeatSetpoint=null, CoolSetpoint=null, StatusHeat=null, VacationHold=null, StatusCool=null, TemporaryHoldUntilTime=null, CoolNextPeriod=null, FanMode=null, SystemSwitch=null, HeatNextPeriod=null}}
That is the "accumulator" and will always show as all = Null since they get cleared, ready for the next batch, as the last thing after each Send to Honeywell. I expect to get get questions about what it's for since it appears to never change. You'd only have 1.6 seconds to see the change