diff --git a/app/controllers/concerns/integrations_actions.rb b/app/controllers/concerns/integrations_actions.rb
index f5a3ec913c2a6089c1d0c7aa29169745a03edf22..fc8d4064b6521e979f937e2e5f06386ff11312f0 100644
--- a/app/controllers/concerns/integrations_actions.rb
+++ b/app/controllers/concerns/integrations_actions.rb
@@ -48,9 +48,12 @@ def reset
 
   private
 
+  # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def integration
     @integration ||= find_or_initialize_non_project_specific_integration(params[:id])
+    @service ||= @integration # TODO: remove references to @service https://gitlab.com/gitlab-org/gitlab/-/issues/329759
   end
+  # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def success_message
     if integration.active?
diff --git a/app/controllers/projects/services_controller.rb b/app/controllers/projects/services_controller.rb
index 74145a70b952b106e1624e16b10f1bf989b97fc4..e72055c3d0f6971fa2a4d9b26d3bc36c0183cbc7 100644
--- a/app/controllers/projects/services_controller.rb
+++ b/app/controllers/projects/services_controller.rb
@@ -85,7 +85,7 @@ def success_message
 
   def integration
     @integration ||= @project.find_or_initialize_service(params[:id])
-    @service ||= @integration # TODO: remove references to @service
+    @service ||= @integration # TODO: remove references to @service https://gitlab.com/gitlab-org/gitlab/-/issues/329759
   end
   alias_method :service, :integration
 
diff --git a/changelogs/unreleased/331262-bugfix-services-variable.yml b/changelogs/unreleased/331262-bugfix-services-variable.yml
new file mode 100644
index 0000000000000000000000000000000000000000..1702f676740f0ae24441f0c8fe0ee4ebeb2aa320
--- /dev/null
+++ b/changelogs/unreleased/331262-bugfix-services-variable.yml
@@ -0,0 +1,5 @@
+---
+title: Fix errors in instance and group-level integration pages for some integrations
+merge_request: 62054
+author:
+type: fixed
diff --git a/spec/features/admin/integrations/user_activates_mattermost_slash_command_spec.rb b/spec/features/admin/integrations/user_activates_mattermost_slash_command_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..6f091d3799503161ea23a2a610be1265f2eab2dc
--- /dev/null
+++ b/spec/features/admin/integrations/user_activates_mattermost_slash_command_spec.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'User activates the instance-level Mattermost Slash Command integration', :js do
+  include_context 'instance integration activation'
+
+  before do
+    stub_mattermost_setting(enabled: true)
+    visit_instance_integration('Mattermost slash commands')
+  end
+
+  let(:edit_path) { edit_admin_application_settings_integration_path(:mattermost_slash_commands) }
+
+  include_examples 'user activates the Mattermost Slash Command integration'
+end
diff --git a/spec/features/groups/integrations/user_activates_mattermost_slash_command_spec.rb b/spec/features/groups/integrations/user_activates_mattermost_slash_command_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..7703268af3944e599fdb9417d9690659c5e232b7
--- /dev/null
+++ b/spec/features/groups/integrations/user_activates_mattermost_slash_command_spec.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'User activates the group-level Mattermost Slash Command integration', :js do
+  include_context 'group integration activation'
+
+  before do
+    stub_mattermost_setting(enabled: true)
+    visit_group_integration('Mattermost slash commands')
+  end
+
+  let(:edit_path) { edit_group_settings_integration_path(group, :mattermost_slash_commands) }
+
+  include_examples 'user activates the Mattermost Slash Command integration'
+end
diff --git a/spec/features/projects/services/user_activates_mattermost_slash_command_spec.rb b/spec/features/projects/services/user_activates_mattermost_slash_command_spec.rb
index 54a501e89a2f46ea11351737c9b711fe1810a7c5..84c9b8c6b54e8017780a5af01ad948327f44c878 100644
--- a/spec/features/projects/services/user_activates_mattermost_slash_command_spec.rb
+++ b/spec/features/projects/services/user_activates_mattermost_slash_command_spec.rb
@@ -14,35 +14,10 @@
     context 'mattermost service is enabled' do
       let(:mattermost_enabled) { true }
 
-      it 'shows a help message' do
-        expect(page).to have_content("Use this service to perform common")
-      end
-
-      it 'shows a token placeholder' do
-        token_placeholder = find_field('service_token')['placeholder']
-
-        expect(token_placeholder).to eq('XXxxXXxxXXxxXXxxXXxxXXxx')
-      end
-
-      it 'redirects to the integrations page after saving but not activating' do
-        token = ('a'..'z').to_a.join
-
-        fill_in 'service_token', with: token
-        click_active_checkbox
-        click_save_integration
-
-        expect(current_path).to eq(edit_project_service_path(project, :mattermost_slash_commands))
-        expect(page).to have_content('Mattermost slash commands settings saved, but not active.')
-      end
-
-      it 'redirects to the integrations page after activating' do
-        token = ('a'..'z').to_a.join
-
-        fill_in 'service_token', with: token
-        click_save_integration
+      describe 'activation' do
+        let(:edit_path) { edit_project_service_path(project, :mattermost_slash_commands) }
 
-        expect(current_path).to eq(edit_project_service_path(project, :mattermost_slash_commands))
-        expect(page).to have_content('Mattermost slash commands settings saved and active.')
+        include_examples 'user activates the Mattermost Slash Command integration'
       end
 
       it 'shows the add to mattermost button' do
diff --git a/spec/support/shared_contexts/features/integrations/group_integrations_shared_context.rb b/spec/support/shared_contexts/features/integrations/group_integrations_shared_context.rb
new file mode 100644
index 0000000000000000000000000000000000000000..5996fcc6593fa113a0b2ae92940edd43ca3ddb81
--- /dev/null
+++ b/spec/support/shared_contexts/features/integrations/group_integrations_shared_context.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+RSpec.shared_context 'group integration activation' do
+  include_context 'instance and group integration activation'
+
+  let_it_be(:group) { create(:group) }
+  let_it_be(:user) { create(:user) }
+
+  before_all do
+    group.add_owner(user)
+  end
+
+  before do
+    sign_in(user)
+  end
+
+  def visit_group_integrations
+    visit group_settings_integrations_path(group)
+  end
+
+  def visit_group_integration(name)
+    visit_group_integrations
+
+    within('#content-body') do
+      click_link(name)
+    end
+  end
+end
diff --git a/spec/support/shared_contexts/features/integrations/instance_and_group_integrations_shared_context.rb b/spec/support/shared_contexts/features/integrations/instance_and_group_integrations_shared_context.rb
new file mode 100644
index 0000000000000000000000000000000000000000..58ee341f71f3a2647265b63dbbbb5658ebb97cb7
--- /dev/null
+++ b/spec/support/shared_contexts/features/integrations/instance_and_group_integrations_shared_context.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+RSpec.shared_context 'instance and group integration activation' do
+  include_context 'integration activation'
+
+  def click_save_integration
+    click_save_changes_button
+    click_save_settings_modal
+  end
+
+  def click_save_changes_button
+    click_button('Save changes')
+  end
+
+  def click_save_settings_modal
+    click_button('Save')
+  end
+end
diff --git a/spec/support/shared_contexts/features/integrations/instance_integrations_shared_context.rb b/spec/support/shared_contexts/features/integrations/instance_integrations_shared_context.rb
new file mode 100644
index 0000000000000000000000000000000000000000..3b02db994a3d643e1a6606400b2a31a95389ad31
--- /dev/null
+++ b/spec/support/shared_contexts/features/integrations/instance_integrations_shared_context.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+RSpec.shared_context 'instance integration activation' do
+  include_context 'instance and group integration activation'
+
+  let_it_be(:user) { create(:user, :admin) }
+
+  before do
+    sign_in(user)
+    gitlab_enable_admin_mode_sign_in(user)
+  end
+
+  def visit_instance_integrations
+    visit integrations_admin_application_settings_path
+  end
+
+  def visit_instance_integration(name)
+    visit_instance_integrations
+
+    within('#content-body') do
+      click_link(name)
+    end
+  end
+end
diff --git a/spec/support/shared_contexts/services_shared_context.rb b/spec/support/shared_contexts/features/integrations/integrations_shared_context.rb
similarity index 95%
rename from spec/support/shared_contexts/services_shared_context.rb
rename to spec/support/shared_contexts/features/integrations/integrations_shared_context.rb
index 34c92367efa0d14cb173983a04490c21949f1893..07c58114b30c37b9566095fa883cafde5346f5f9 100644
--- a/spec/support/shared_contexts/services_shared_context.rb
+++ b/spec/support/shared_contexts/features/integrations/integrations_shared_context.rb
@@ -70,3 +70,9 @@ def enable_license_for_service(service)
     end
   end
 end
+
+RSpec.shared_context 'integration activation' do
+  def click_active_checkbox
+    find('label', text: 'Active').click
+  end
+end
diff --git a/spec/support/shared_contexts/project_service_jira_context.rb b/spec/support/shared_contexts/features/integrations/project_integrations_jira_context.rb
similarity index 100%
rename from spec/support/shared_contexts/project_service_jira_context.rb
rename to spec/support/shared_contexts/features/integrations/project_integrations_jira_context.rb
diff --git a/spec/support/shared_contexts/project_service_shared_context.rb b/spec/support/shared_contexts/features/integrations/project_integrations_shared_context.rb
similarity index 92%
rename from spec/support/shared_contexts/project_service_shared_context.rb
rename to spec/support/shared_contexts/features/integrations/project_integrations_shared_context.rb
index 0e3540a3e156d663a7011ccf892809c3df089bfd..b10844320d06c97862d2e6dc3c9d303ebc5c0e0a 100644
--- a/spec/support/shared_contexts/project_service_shared_context.rb
+++ b/spec/support/shared_contexts/features/integrations/project_integrations_shared_context.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 RSpec.shared_context 'project service activation' do
+  include_context 'integration activation'
+
   let(:project) { create(:project) }
   let(:user) { create(:user) }
 
@@ -21,10 +23,6 @@ def visit_project_integration(name)
     end
   end
 
-  def click_active_checkbox
-    find('label', text: 'Active').click
-  end
-
   def click_save_integration
     click_button('Save changes')
   end
diff --git a/spec/support/shared_examples/features/integrations/user_activates_mattermost_slash_command_integration_shared_examples.rb b/spec/support/shared_examples/features/integrations/user_activates_mattermost_slash_command_integration_shared_examples.rb
new file mode 100644
index 0000000000000000000000000000000000000000..cfa043322db56069299b492f957efa34c77c356e
--- /dev/null
+++ b/spec/support/shared_examples/features/integrations/user_activates_mattermost_slash_command_integration_shared_examples.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+RSpec.shared_examples 'user activates the Mattermost Slash Command integration' do
+  it 'shows a help message' do
+    expect(page).to have_content('Use this service to perform common')
+  end
+
+  it 'shows a token placeholder' do
+    token_placeholder = find_field('service_token')['placeholder']
+
+    expect(token_placeholder).to eq('XXxxXXxxXXxxXXxxXXxxXXxx')
+  end
+
+  it 'redirects to the integrations page after saving but not activating' do
+    token = ('a'..'z').to_a.join
+
+    fill_in 'service_token', with: token
+    click_active_checkbox
+    click_save_integration
+
+    expect(current_path).to eq(edit_path)
+    expect(page).to have_content('Mattermost slash commands settings saved, but not active.')
+  end
+
+  it 'redirects to the integrations page after activating' do
+    token = ('a'..'z').to_a.join
+
+    fill_in 'service_token', with: token
+    click_save_integration
+
+    expect(current_path).to eq(edit_path)
+    expect(page).to have_content('Mattermost slash commands settings saved and active.')
+  end
+end