diff --git a/packages/core/src/entity/order-item/order-item.entity.ts b/packages/core/src/entity/order-item/order-item.entity.ts
index 729a6bcf28..ed42a204db 100644
--- a/packages/core/src/entity/order-item/order-item.entity.ts
+++ b/packages/core/src/entity/order-item/order-item.entity.ts
@@ -28,7 +28,7 @@ export class OrderItem extends VendureEntity {
     line: OrderLine;
 
     @EntityId()
-    lineId: ID;
+    lineId: ID; // TypeORM requires this ID field on the entity explicitly in order to save the foreign key via `.insert`
 
     /**
      * @description
diff --git a/packages/core/src/service/helpers/order-modifier/order-modifier.ts b/packages/core/src/service/helpers/order-modifier/order-modifier.ts
index f6122c94b4..211bbc53a5 100644
--- a/packages/core/src/service/helpers/order-modifier/order-modifier.ts
+++ b/packages/core/src/service/helpers/order-modifier/order-modifier.ts
@@ -158,7 +158,7 @@ export class OrderModifier {
                         listPriceIncludesTax: orderLine.productVariant.priceIncludesTax,
                         adjustments: [],
                         taxLines: [],
-                        line: orderLine,
+                        lineId: orderLine.id,
                     }),
                 );
             }
diff --git a/packages/core/src/service/services/order.service.ts b/packages/core/src/service/services/order.service.ts
index 79e76c2eb8..9fb702c2be 100644
--- a/packages/core/src/service/services/order.service.ts
+++ b/packages/core/src/service/services/order.service.ts
@@ -1328,7 +1328,13 @@ export class OrderService {
             promotions,
             updatedOrderLine ? [updatedOrderLine] : [],
         );
-        // await this.connection.getRepository(ctx, OrderItem).save(updatedItems, { reload: false });
+        const updateFields: Array<keyof OrderItem> = [
+            'initialListPrice',
+            'listPrice',
+            'listPriceIncludesTax',
+            'adjustments',
+            'taxLines',
+        ];
         await this.connection
             .getRepository(ctx, OrderItem)
             .createQueryBuilder()
@@ -1336,13 +1342,7 @@ export class OrderService {
             .values(updatedItems)
             .orUpdate({
                 conflict_target: ['id'],
-                overwrite: [
-                    'initialListPrice',
-                    'listPrice',
-                    'listPriceIncludesTax',
-                    'adjustments',
-                    'taxLines',
-                ],
+                overwrite: updateFields,
             })
             .updateEntity(false)
             .execute();