SharedShelfLink publishAction bug?

In the publishAction function of the SharedShelfLink_PublishingController, execution never gets past the json helper function. Why?

Is this a bug? Is this a known bug?


class SharedShelfLink_PublishingController extends Omeka_Controller_AbstractActionController
{
/**
* Handle the publishing request from Shared Shelf.
*
* @return void
*/
public function publishAction()
{
// Bypass ACL security on publication processing.
//Omeka_Context::getInstance()->acl = null;

error_log(date('Y-m-d H:i:s') . ' SSID ' . $_POST['_ss_id'] . " Publish start\n", 3, '/var/www/html/publog');

$token = get_option('shared_shelf_link_token');
if ($token == $_POST['__token']) {
new SharedShelfImporter();
$publication = new SharedShelfImporter;
$publication->createOrUpdateItem($_POST, $_FILES);
$this->_helper->json(array('success' => true)); // Execution never returns from this function. Why?
} else {
$this->_helper->json(array('success' => false)); // Execution never returns from this function. Why?
}

// Never gets here

error_log(date('Y-m-d H:i:s') . ' SSID ' . $_POST['_ss_id'] . " Publish end\n\n", 3, '/var/www/html/publog');

}
/...

The json helper (which comes from Zend) exits immediately after it's called.