diff -u b/modules/cart/src/Form/AddToCartForm.php b/modules/cart/src/Form/AddToCartForm.php
--- b/modules/cart/src/Form/AddToCartForm.php	(date 1701797111222)
+++ b/modules/cart/src/Form/AddToCartForm.php	(date 1709129964342)
@@ -232,16 +232,35 @@
       $this->getDestination($form_state) === 'checkout' &&
       $this->moduleHandler->moduleExists('commerce_checkout')
     ) {
-      /** @var \Drupal\commerce_order\Entity\OrderInterface $order */
-      $order = $this->entityTypeManager->getStorage('commerce_order')
-        ->create([
+      $order = NULL;
+      $order_storage = $this->entityTypeManager->getStorage('commerce_order');
+
+      // For authenticated user, try to get existing draft order to reduce
+      // duplicates for the same item.
+      if ($this->currentUser->isAuthenticated()) {
+        $order_ids = $order_storage->getQuery()
+          ->condition('type', $order_type_id)
+          ->condition('store_id', $store->id())
+          ->condition('uid', $this->currentUser->id())
+          ->condition('state', 'draft')
+          ->condition('order_items.entity.purchased_entity', $purchased_entity->id())
+          ->accessCheck()
+          ->execute();
+        if (!empty($order_ids)) {
+          $order = $order_storage->load(reset($order_ids));
+        }
+      }
+      if (!$order) {
+        /** @var \Drupal\commerce_order\Entity\OrderInterface $order */
+        $order_storage->create([
           'type' => $order_type_id,
           'store_id' => $store->id(),
           'uid' => $this->currentUser()->id(),
           'cart' => FALSE,
         ]);
-      $order->addItem($order_item);
-      $order->save();
+        $order->addItem($order_item);
+        $order->save();
+      }
 
       // Add the order as a completed cart to allow anonymous checkout access.
       // @todo Find a better way for this.
reverted:
--- b/modules/product/tests/src/FunctionalJavascript/ProductLayoutBuilderIntegrationTest.php	(date 1701797107377)
+++ a/modules/product/tests/src/FunctionalJavascript/ProductLayoutBuilderIntegrationTest.php	(revision 8ea8a7ecfcffcd4da5998763302f76746078013b)
@@ -290,7 +290,6 @@
     $save_layout = $this->getSession()->getPage()->findButton('Save layout');
     $save_layout->focus();
     $save_layout->click();
-    $this->assertSession()->waitForElementVisible('css', '.messages-list__wrapper');
     $this->assertSession()->pageTextContains('The layout has been saved.');
   }