diff --git a/assets/js/src/segments/list.jsx b/assets/js/src/segments/list.jsx
index 3ab1a5c8db..a39776ea08 100644
--- a/assets/js/src/segments/list.jsx
+++ b/assets/js/src/segments/list.jsx
@@ -156,14 +156,12 @@ const item_actions = [
         api_version: window.mailpoet_api_version,
         endpoint: 'segments',
         action: 'synchronize'
-      }).done((response) => {
+      }).done(() => {
         MailPoet.Modal.loading(false);
-        if(response === true) {
-          MailPoet.Notice.success(
-            (MailPoet.I18n.t('listSynchronized')).replace('%$1s', item.name)
-          );
-          refresh();
-        }
+        MailPoet.Notice.success(
+          (MailPoet.I18n.t('listSynchronized')).replace('%$1s', item.name)
+        );
+        refresh();
       }).fail((response) => {
         MailPoet.Modal.loading(false);
         if(response.errors.length > 0) {
diff --git a/lib/Segments/WP.php b/lib/Segments/WP.php
index e0e01b4600..eceaecccca 100644
--- a/lib/Segments/WP.php
+++ b/lib/Segments/WP.php
@@ -26,13 +26,9 @@ class WP {
       case 'deleted_user':
       case 'remove_user_from_blog':
         if($subscriber !== false) {
-          // unlink subscriber to wp user
-          $subscriber->setExpr('wp_user_id', 'NULL')->save();
-
-          // delete subscription to wp segment
-          SubscriberSegment::where('subscriber_id', $subscriber->id)
-            ->where('segment_id', $wp_segment->id)
-            ->deleteMany();
+          // unlink subscriber from wp user and delete
+          $subscriber->set('wp_user_id', null);
+          $subscriber->delete();
         }
         break;
       case 'profile_update':
@@ -97,6 +93,14 @@ class WP {
       static::synchronizeUser($wp_user_id);
     }
 
+    // remove orphaned wp segment subscribers (not having a matching wp user id),
+    // e.g. if wp users were deleted directly from the database
+    $wp_segment->subscribers()
+      ->whereNotIn('wp_user_id', $wp_users)
+      ->findResultSet()
+      ->set('wp_user_id', null)
+      ->delete();
+
     return true;
   }
 }