Form editor Hidden property not work correctly

I have issue when I'm trying appear and disappear text based on condition (boolean data variable)
even the value become false - so the text must appear - nothing show.
I test that the value become true and false multiple time still the same.

api external name : restResult
api external value : ../API/bpm/caseVariable/{{task.rootCaseId}}/errorHide
hidden property fx defined as "restResult.value"

note that 'errorHide' variable declare as boolean process variable.