diff --git a/app/models/invitation.rb b/app/models/invitation.rb
index 348fb37b68..9de9d0465e 100644
--- a/app/models/invitation.rb
+++ b/app/models/invitation.rb
@@ -24,7 +24,7 @@ class Invitation < ApplicationRecord
 
   # Build new user on information in this invitation.
   def make_user(params = {})
-    self.user = account.users.build_with_fields params.reverse_merge(email: email, invitation: self)
+    self.user = account.users.build_with_fields params.reverse_merge(email: email)
   end
 
   def accepted?
diff --git a/app/models/user/invitations.rb b/app/models/user/invitations.rb
index 53a51611ee..fb7904fd2e 100644
--- a/app/models/user/invitations.rb
+++ b/app/models/user/invitations.rb
@@ -4,10 +4,7 @@ module User::Invitations
   included do
     after_commit :accept_invitation, :on => :create
 
-    attr_accessor :invitation
-
-    # TODO: refactor to make this work removing above attribute.
-    # has_one :invitation
+    has_one :invitation # rubocop:disable Rails/HasManyOrHasOneDependent -- before_destroy :destroy_invitation handles it
 
     before_destroy :destroy_invitation
   end
@@ -18,7 +15,8 @@ def accept_invitation
 
   def destroy_invitation
     if account # some tests fail because of account being nil
-      invit = account.invitations.find_by_email(email) || account.invitations.find_by_user_id(id) # || eventually invitation
+      invitations = account.invitations
+      invit = invitations.find_by(email: email) || invitations.find_by(user_id: id)
       # halt the destruction if the destruction of invitation failed
       throw :abort if invit && invit.destroy == false
     end
diff --git a/test/integration/developer_portal/accounts/invitee_signups_controller_test.rb b/test/integration/developer_portal/accounts/invitee_signups_controller_test.rb
index 03c6a4fe71..5121e07258 100644
--- a/test/integration/developer_portal/accounts/invitee_signups_controller_test.rb
+++ b/test/integration/developer_portal/accounts/invitee_signups_controller_test.rb
@@ -46,6 +46,7 @@ def setup
 
     assert_equal I18n.t('developer_portal.accounts.invitee_signups.create.success'), flash[:notice]
     assert_redirected_to login_path
+    assert invitation.reload.accepted?
   end
 
   test 'create pushes webhook' do
diff --git a/test/integration/provider/invitee_signups_controller_integration_test.rb b/test/integration/provider/invitee_signups_controller_integration_test.rb
index e3943dea13..cba9d25ded 100644
--- a/test/integration/provider/invitee_signups_controller_integration_test.rb
+++ b/test/integration/provider/invitee_signups_controller_integration_test.rb
@@ -26,6 +26,7 @@ def setup
 
     assert_equal I18n.t('provider.invitee_signups.create.success'), flash[:success]
     assert_redirected_to provider_login_path
+    assert invitation.reload.accepted?
   end
 
   test 'do not set unpermitted attributes' do
diff --git a/test/unit/authentication/strategy/oauth2_test.rb b/test/unit/authentication/strategy/oauth2_test.rb
index 2815f444f3..d2ae3342ef 100644
--- a/test/unit/authentication/strategy/oauth2_test.rb
+++ b/test/unit/authentication/strategy/oauth2_test.rb
@@ -334,6 +334,7 @@ class SsoSignupTest < ActiveSupport::TestCase
           assert_equal result.username, user_data[:username]
           assert result.active?
           assert authentication_strategy.error_message.blank?
+          assert invitation.reload.accepted?
         end
       end
     end
diff --git a/test/unit/authentication/strategy/provider_oauth2_test.rb b/test/unit/authentication/strategy/provider_oauth2_test.rb
index 59e9bf422e..276db8e3fc 100644
--- a/test/unit/authentication/strategy/provider_oauth2_test.rb
+++ b/test/unit/authentication/strategy/provider_oauth2_test.rb
@@ -258,6 +258,7 @@ class SsoSignupTest < ActiveSupport::TestCase
           assert_equal result.username, user_data[:username]
           assert result.active?
           assert authentication_strategy.error_message.blank?
+          assert invitation.reload.accepted?
         end
       end
     end