Issue Summary:

When wp_cache_set() is triggered from the WordPress admin panel (wp-admin), W3 Total Cache disables object cache storage due to the following condition inside _check_can_cache_runtime():

if (
$this->_caching
&& defined( ‘WP_ADMIN’ )
&& ( ! defined( ‘DOING_AJAX’ ) || ! DOING_AJAX )
) {
$this->_can_cache_dynamic = false;
$this->cache_reject_reason = ‘WP_ADMIN defined’;

return $this->_can_cache_dynamic;
}

Configuration Details:

In the W3TC Dashboard:

Performance → Object Cache → Advanced (/wp-admin/admin.php?page=w3tc_objectcache)

the option: Enable caching for wp-admin requests is currently disabled.

Problem:

Because of this configuration and the above condition, object cache operations are skipped for all non-AJAX wp-admin requests.

As a result, when settings are updated from the admin panel and wp_cache_set() is called during the save process, the cache is not refreshed/updated in Redis/Memcached/object cache storage.

This leads to stale data being served on the frontend.

Example Scenario:

User updates General Settings from WordPress admin
wp_cache_set() is executed during settings save
Since request originates from wp-admin, _check_can_cache_runtime() returns false
Object cache update is skipped
Frontend continues showing old cached values until cache expiry/manual purge