diff --git a/app/models/notifications/mentioned_in_comment.rb b/app/models/notifications/mentioned_in_comment.rb
index 5e5466b68..5b57f395b 100644
--- a/app/models/notifications/mentioned_in_comment.rb
+++ b/app/models/notifications/mentioned_in_comment.rb
@@ -11,7 +11,7 @@ module Notifications
     end
 
     def self.filter_mentions(mentions, mentionable, _recipient_user_ids)
-      mentions.joins(:person).merge(Person.allowed_to_be_mentioned_in_a_comment_to(mentionable.parent))
+      mentions.includes(:person).merge(Person.allowed_to_be_mentioned_in_a_comment_to(mentionable.parent)).distinct
     end
 
     def mail_job
diff --git a/spec/integration/mentioning_spec.rb b/spec/integration/mentioning_spec.rb
index 2e6b4292d..367758bf8 100644
--- a/spec/integration/mentioning_spec.rb
+++ b/spec/integration/mentioning_spec.rb
@@ -376,6 +376,18 @@ describe "mentioning", type: :request do
           end
         end
       end
+
+      it "only creates one notification for the mentioned person, when mentioned person commented twice before" do
+        parent = FactoryGirl.create(:status_message_in_aspect, author: author.person)
+        mentioned_user = FactoryGirl.create(:user_with_aspect, friends: [author])
+        mentioned_user.comment!(parent, "test comment 1")
+        mentioned_user.comment!(parent, "test comment 2")
+        comment = inlined_jobs do
+          author.comment!(parent, text_mentioning(mentioned_user))
+        end
+
+        expect(notifications_about_mentioning(mentioned_user, comment).count).to eq(1)
+      end
     end
   end
 end