diff --git a/app/controllers/auth_services_controller.rb b/app/controllers/auth_services_controller.rb
index 83af48b35..84c004356 100644
--- a/app/controllers/auth_services_controller.rb
+++ b/app/controllers/auth_services_controller.rb
@@ -35,6 +35,7 @@ def create
 
         member = Member.find_by(email:)
         member ||= Member.new(email:)
+        new_member = member.new_record?
 
         member.name    ||= omnihash[:info][:name]&.split(' ')&.first || ''
         member.surname ||= omnihash[:info][:name]&.split(' ')&.drop(1)&.join(' ') || ''
@@ -55,6 +56,7 @@ def create
           member_service = AuthService.find_by!(provider: omnihash[:provider],
                                                 uid: omnihash[:uid])
           member = member_service.member
+          new_member = false
         end
 
         session[:member_id]          = member.id
@@ -63,6 +65,7 @@ def create
         session[:oauth_token_secret] = omnihash[:credentials][:secret]
 
         if member.requires_additional_details?
+          session[:new_member] = new_member
           redirect_to edit_member_details_path(member_type:)
         else
           redirect_to referer_or_dashboard_path
diff --git a/app/controllers/member/details_controller.rb b/app/controllers/member/details_controller.rb
index 14cc0c711..6800f420e 100644
--- a/app/controllers/member/details_controller.rb
+++ b/app/controllers/member/details_controller.rb
@@ -8,7 +8,9 @@ class Member::DetailsController < ApplicationController
 
   def edit
     accept_terms
-    flash[notice] = I18n.t('notifications.signing_up')
+    if session.delete(:new_member)
+      flash[notice] = I18n.t('notifications.signing_up')
+    end
     @member.newsletter ||= true
   end
 
diff --git a/spec/controllers/member/details_controller_spec.rb b/spec/controllers/member/details_controller_spec.rb
index d0db8a953..6e4bbf1f8 100644
--- a/spec/controllers/member/details_controller_spec.rb
+++ b/spec/controllers/member/details_controller_spec.rb
@@ -9,6 +9,28 @@
     allow(mailing_list).to receive_messages(subscribe: true, unsubscribe: true)
   end
 
+  describe 'GET #edit' do
+    context 'when a brand-new member' do
+      it 'shows the signing up message' do
+        session[:new_member] = true
+
+        get :edit
+
+        expect(response.body).to include(I18n.t('notifications.signing_up'))
+      end
+    end
+
+    context 'when an existing member' do
+      it 'does not show the signing up message' do
+        session[:new_member] = false
+
+        get :edit
+
+        expect(response.body).not_to include(I18n.t('notifications.signing_up'))
+      end
+    end
+  end
+
   describe 'PATCH #update' do
     context 'with valid params' do
       it 'updates how_you_found_us with radio option' do
diff --git a/spec/requests/auth_services_callback_spec.rb b/spec/requests/auth_services_callback_spec.rb
index 1110989b6..71c256ef0 100644
--- a/spec/requests/auth_services_callback_spec.rb
+++ b/spec/requests/auth_services_callback_spec.rb
@@ -57,5 +57,21 @@
     post '/auth/github/callback'
 
     expect(response).to redirect_to(edit_member_details_path)
+    expect(session[:new_member]).to be(true)
+  end
+
+  it 'does not mark an existing incomplete member as a new signup when they return to complete their profile' do
+    returning = Fabricate(:member, name: nil, surname: nil, about_you: nil,
+                                   email: 'returning@example.com')
+    returning.auth_services.delete_all
+    svc = Fabricate(:auth_service, member: returning,
+                                   provider: 'github', uid: 'returning-github-uid')
+    mock_auth_hash(provider: 'github', uid: svc.uid,
+                   email: 'returning@example.com', name: nil)
+
+    post '/auth/github/callback'
+
+    expect(response).to redirect_to(edit_member_details_path)
+    expect(session[:new_member]).to be_nil
   end
 end