diff --git a/app/models/topic_user.rb b/app/models/topic_user.rb
index eb6cceeaf59..6395394e630 100644
--- a/app/models/topic_user.rb
+++ b/app/models/topic_user.rb
@@ -38,7 +38,8 @@ class TopicUser < ActiveRecord::Base
     end
 
     def auto_notification(user_id, topic_id, reason, notification_level)
-      if TopicUser.where(user_id: user_id, topic_id: topic_id, notifications_reason_id: nil).exists?
+      if TopicUser.where("user_id = ? AND topic_id = ? AND (notifications_reason_id IS NULL OR notification_level < ?)",
+                           user_id, topic_id, notification_level).exists?
         change(user_id, topic_id,
           notification_level: notification_level,
           notifications_reason_id: reason