Please note that regardless of TRVZB Close % setting if the valve is in 'OFF (Frost-protection) Thermostat mode it will close fully to 100% if the ambient temperature is above the target temperature (Valve ‘Keeping’).
Why would this cause problems ? Only relevant to situations that use a valve or valves that are set slightly open while ‘Keeping’ to allow a circulation path between flow and return in case the boiler’s frost protection thermostat causes it to fire up.