After enabling complete null support, I assumed that any native data type would accept the value Null however, only String and Numeric did. I compared this behavior with ACF 2018 with null support enabled as well and it seems to handle it like I expected.
"Message":invalid call of the function createPerson, 3th Argument (isDeveloper) is of invalid type, can't cast Null value to value of type [boolean]
"Message": "invalid call of the function createPerson, 4th Argument (birthdate) is of invalid type, can't cast Null value to value of type [date]"
Same type of error with the rest of the parameters
I've checked this ticket & confirmed the issue happened on both lucee affected version and the latest version 188.8.131.52 also. But, ACF doesn't throw any error for this.