MAGETWO-81326: [Fix:5439] Send email to subscribers only when are new 2.2 [Backport] #11317

app/code/Magento/Newsletter/Model/Subscriber.php

@@ -395,6 +395,10 @@ class Subscriber extends \Magento\Framework\Model\AbstractModel
     {
         $this->loadByEmail($email);
 
+        if ($this->getId() && $this->getStatus() == self::STATUS_SUBSCRIBED) {
+            return $this->getStatus();
+        }
+
         if (!$this->getId()) {
             $this->setSubscriberConfirmCode($this->randomSequence());
         }