As I mentioned above you can simply set the default value to “null” and that way no value will be selected by default. And you don’t need to remove “null” via javascript as it won’t show on the frontend at all by default. Just make sure you add “null” to the default value field and not in the list of other normal values.
However, the radio button defaulting to the first field still appears to a bug that should be addressed by ACF.
