can't get update_field and get_fields to work

Hi, i am creating a post and inserting the acf fields programmatically. I can't get the get_fields function or update_fields function to work as they usually do.

update_fields() returns a number and get_fields() returns nothing

here is some example code

// Create new post.
$post_data = array(
	'post_title'    => 'My post',
	'post_type'     => 'post',
	'post_status'   => 'publish'
);
$post_id = wp_insert_post($post_data);

// Save a basic text value.
$field_key = "field_123456";
$value = "some new string";
// update_field($field_key, $value, $post_id);

$update = update_field($field_key, $value, $post_id);

$fields = get_fields($post_id);

echo $update; // returns - 9215

echo $fields; // returns blank

any help would be much appreciated.

Start by reproducing the example in issue #324 with wp_insert_post(), update_field(), and get_fields(). Read the ACF documentation and the implementation of these functions to determine why the reported return values occur. Done means identifying the cause and documenting or verifying the expected behavior.