Hi Tringwebdesign,
I think it’s not working because you try to save the $field[“choices”] in $field, try this :
function sort_checkbox( $field ) {
$field["choices"] = sort($field["choices"]);
return $field;
}
add_filter('acf/load_field/key=field_5d4164d40898f', 'sort_checkbox');
I assume the sort method you use is correct, it’s may not.