diff --git a/app/models/project_services/chat_message/merge_message.rb b/app/models/project_services/chat_message/merge_message.rb
index cc88d57faf8..6b7a35aaa75 100644
--- a/app/models/project_services/chat_message/merge_message.rb
+++ b/app/models/project_services/chat_message/merge_message.rb
@@ -26,7 +26,7 @@ module ChatMessage
 
     def activity
       {
-        title: "Merge Request #{state} by #{user_combined_name}",
+        title: "Merge Request #{state_or_action_text} by #{user_combined_name}",
         subtitle: "in #{project_link}",
         text: merge_request_link,
         image: user_avatar
diff --git a/changelogs/unreleased/fix-chat-notification-service-for-ee.yml b/changelogs/unreleased/fix-chat-notification-service-for-ee.yml
new file mode 100644
index 00000000000..b69d08b95db
--- /dev/null
+++ b/changelogs/unreleased/fix-chat-notification-service-for-ee.yml
@@ -0,0 +1,5 @@
+---
+title: Fix activity titles for MRs in chat notification services
+merge_request: 21834
+author:
+type: fixed
diff --git a/spec/models/project_services/chat_message/merge_message_spec.rb b/spec/models/project_services/chat_message/merge_message_spec.rb
index 96496295825..7997b5bb6b9 100644
--- a/spec/models/project_services/chat_message/merge_message_spec.rb
+++ b/spec/models/project_services/chat_message/merge_message_spec.rb
@@ -27,6 +27,23 @@ describe ChatMessage::MergeMessage do
     }
   end
 
+  # Integration point in EE
+  context 'when state is overridden' do
+    it 'respects the overridden state' do
+      allow(subject).to receive(:state_or_action_text) { 'devoured' }
+
+      aggregate_failures do
+        expect(subject.summary).not_to include('opened')
+        expect(subject.summary).to include('devoured')
+
+        activity_title = subject.activity[:title]
+
+        expect(activity_title).not_to include('opened')
+        expect(activity_title).to include('devoured')
+      end
+    end
+  end
+
   context 'without markdown' do
     let(:color) { '#345' }