diff -u b/modules/promotion/src/Plugin/Commerce/PromotionOffer/BuyXGetY.php b/modules/promotion/src/Plugin/Commerce/PromotionOffer/BuyXGetY.php
--- b/modules/promotion/src/Plugin/Commerce/PromotionOffer/BuyXGetY.php
+++ b/modules/promotion/src/Plugin/Commerce/PromotionOffer/BuyXGetY.php
@@ -467,6 +467,9 @@
         return $order_item->getData("promotion:{$promotion->id()}:auto_add_quantity");
       });
       foreach ($auto_add_order_items as $order_item) {
+        $order_item->setAdjustments(array_filter($order_item->getAdjustments(), function (Adjustment $adjustment) use ($promotion) {
+          return $adjustment->getSourceId() !== $promotion->id();
+        }));
         $new_quantity = Calculator::subtract($order_item->getQuantity(), $order_item->getData("promotion:{$promotion->id()}:auto_add_quantity"));
         $order_item->setQuantity($new_quantity);
       }