diff --git a/CHANGELOG b/CHANGELOG
index 24ce5495e1b..9cc762e3263 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -99,7 +99,6 @@
 * FlexCharge: Update homePage url [javierpedrozaing] #5351
 * Nuvei: Fix send savePM in false by default [javierpedrozaing] #5353
 * Decidir and DecicirPlus: Add the wallet_id field [yunnydang] #5354
-* Worldpay: Idempotency key fix [jherreraa] #5343
 
 == Version 1.137.0 (August 2, 2024)
 * Unlock dependency on `rexml` to allow fixing a CVE (#5181).
diff --git a/lib/active_merchant/billing/gateways/worldpay.rb b/lib/active_merchant/billing/gateways/worldpay.rb
index 67ea78c7f0b..52b629ebc28 100644
--- a/lib/active_merchant/billing/gateways/worldpay.rb
+++ b/lib/active_merchant/billing/gateways/worldpay.rb
@@ -954,12 +954,7 @@ def headers(options)
         cookie = options[:cookie] || cookie
         headers['Cookie'] = cookie if cookie
 
-        # Required because Worldpay does not accept duplicate idempotency keys
-        # for different transactions, such as in the case of an authorize => capture flow.
-        if idempotency_key
-          headers['Idempotency-Key'] = idempotency_key
-          options[:idempotency_key] = SecureRandom.uuid
-        end
+        headers['Idempotency-Key'] = idempotency_key if idempotency_key
         headers
       end
 
diff --git a/test/remote/gateways/remote_worldpay_test.rb b/test/remote/gateways/remote_worldpay_test.rb
index 5cdacb7d3fb..3296e33785c 100644
--- a/test/remote/gateways/remote_worldpay_test.rb
+++ b/test/remote/gateways/remote_worldpay_test.rb
@@ -306,8 +306,8 @@ def test_unsucessfull_authorize_without_token_number_apple_pay
     response = @gateway.authorize(@amount, @apple_pay_network_token, @options)
 
     assert_failure response
-    assert_equal response.error_code, '2'
-    assert_match "Missing required elements 'tokenNumber'", response.message
+    assert_equal response.error_code, '5'
+    assert_equal "Element 'tokenNumber' must have valid numeric content.", response.message
   end
 
   def test_unsucessfull_authorize_with_token_number_as_empty_string_apple_pay
@@ -315,8 +315,8 @@ def test_unsucessfull_authorize_with_token_number_as_empty_string_apple_pay
     response = @gateway.authorize(@amount, @apple_pay_network_token, @options)
 
     assert_failure response
-    assert_equal response.error_code, '2'
-    assert_match "Missing required elements 'tokenNumber'", response.message
+    assert_equal response.error_code, '5'
+    assert_equal "Element 'tokenNumber' must have valid numeric content.", response.message
   end
 
   def test_unsucessfull_authorize_with_invalid_token_number_apple_pay
@@ -1342,7 +1342,7 @@ def test_failed_refund_synchronous_response
 
     refund = @cftgateway.refund(@amount * 2, auth.authorization, authorization_validated: true)
     assert_failure refund
-    assert_equal 'Invalid amount: The refund amount should be equal to the captured value', refund.message
+    assert_equal 'Refund amount too high', refund.message
   end
 
   def test_successful_purchase_with_options_synchronous_response
diff --git a/test/unit/gateways/worldpay_test.rb b/test/unit/gateways/worldpay_test.rb
index 3d70eacf27c..8f173ec9409 100644
--- a/test/unit/gateways/worldpay_test.rb
+++ b/test/unit/gateways/worldpay_test.rb
@@ -223,12 +223,6 @@ def test_payment_type_for_credit_card
     assert_equal payment, :credit
   end
 
-  def test_idempotency_header
-    options = { idempotency_key: 'test123' }
-    headers = @gateway.send(:headers, options)
-    assert_not_equal options[:idempotency_key], headers['Idempotency-Key']
-  end
-
   def test_successful_authorize
     response = stub_comms do
       @gateway.authorize(@amount, @credit_card, @options)