get_field() return old values

Question

I have a problem with get_field(). This function doesn't return the last inserted value with previously created fields. If i create a new field, get_field() doesn't return any value. All the value are correctly stored on database. What could be the problem? I have ACF 5.8.0 and Wordpress 5.2.

EDIT

<?php /* Template Name: Chi Siamo */ ?>
<?php get_header(); ?>

<?php $address_map = get_field('indirizzo_mappa'); ?>

<div id="aboutUs" class="container">

    <?php while ( have_posts() ) : the_post(); ?>
    <div class="title">
        <?php the_title(); ?>
    </div>
    <div class="content">
        <?php the_content(); ?>
    </div>
    <?php endwhile; ?>

</div>

<?php if ($address_map) : ?>
<h1 class="mapTitle"><?php echo __('WHERE WE ARE','noisegallery'); ?></h1>
<div id="map" data-address="<?php echo $address_map; ?>"></div>
<?php endif;?>

<div class="firma">Designed from scratch by <b><a target="_blank" href="http://hellodude.it">DUDE</a></b></div>

<?php get_footer(); ?>

Answer 1

One of the reasons (apart from cache not being cleared) is duplicated field_xxx post_name rows in wp_posts table. The reason is usually connected with exporting/importing fields or db changes during major plugin update (at least some users reported that).

When it happens, you get values from latest post in wp-admin and in acf/save_post hook, but when you're trying to get_field you get only values from oldest post of the same field_xxx.

You can easily check if that's the case with following query:

select post_name, count(ID) c, group_concat(ID) 
from wp_posts 
where post_type='acf-field'
group by post_name
having c>1;

If there are any values in results it's problably it. You can safely remove duplicated values starting from oldest post.

Of course you should create backup before doing that - export all acf fields to json file and make a dump od database.

In case there are many of them you can use this script which will leave highest ID of each duplicate fields and remove all duplicates.

include_once "wp-config.php";
include_once "wp-includes/wp-db.php";

$query = "select post_name, count(ID) c, group_concat(ID) gc from wp_posts where post_type='acf-field'
group by post_name
having c>1;";

$rows = $wpdb->get_results($query);

foreach ($rows as $row) {
    $duplicatedIds = explode(',', $row['gc']);

    $highestId = max($duplicatedIds);

    $keyToPreserve = array_search($highestId, $duplicatedIds);

    unset($duplicatedIds[$keyToPreserve]);

    $toRemoveIds = implode(',', $duplicatedIds);

    echo "- Removing duplicated posts from field {$row['post_name']}: $toRemoveIds. Preserving {$highestId}.\n";

    foreach ($duplicatedIds as $postId) {
        wp_delete_post($postId);
    }
}

wp_cache_flush();

After removing duplicated rows from database problem should not exist anymore. If you're using W3 Cache or any other cache plugin, you should purge it's cache as well.