After further investigation of that issue we might have found the “bug”

Looking at td_review.php you find the following code snippet:


static function save_post_hook($post_id) {
//$td_review = get_post_meta($post_id, 'td_review', true);
$td_review = get_post_meta($post_id, 'td_post_theme_settings', true);
if (self::has_review($td_review)) {
update_post_meta($post_id, self::$td_review_key, self::calculate_total_key_value($td_review));
}


Just maybe there is an else snippet missing to remove the td_review_key in case someone “disables” the review for a post?!
Anyhow, for our problem we manually removed the entry from the database to synchronize the backend view and the db.

Cheers!