Ah, you are right – when using the “Only if the field is empty” checkbox the value is not properly validated as empty and the field will not be set. I’ll get this fixed in the next release.
Until then, you can put this in your Custom JS:
function setDataConfidentialityToPrivate(){
if(String(getFieldValue("YOUR_FIELD_NAME")).length === 0){
setFieldValue("YOUR_FIELD_NAME", "YOUR_VALUE");
}
}
And put the function name setDataConfidentialityToPrivate in the Run these functions / trigger these rules field in your rule.
Replace YOUR_FIELD_NAME and YOUR_VALUE with the correct values.
Alexander