### Preconditions (*) - Inventory Metapackage Version: 1.2.8-p3 - Product Type: Simple with Custom Options - Advanced Inventory > Backorders = Allow Qty Below 0 and Notify Customer ### Steps to reproduce (*) - Create a simple product with custom options. - Set product stock quantity to 10. <img width="1813" height="2187" alt="Image" src="https://github.com/user-attachments/assets/aac07464-5e6b-4f51-afba-d712046c698b" /> - Enable backorders: Catalog > Products > Advanced Inventory > Backorders > Allow Qty Below 0 and Notify Customer - On frontend, add the same product to the cart twice, each with a different custom option. For each cart item, set quantity to 20. <img width="1920" height="877" alt="Image" src="https://github.com/user-attachments/assets/6a7c95e7-903c-408a-b5d7-5a0d09c4761e" /> ### Expected result (*) Cart should show correct stock/backorder distribution per line item: - First cart item: - Qty ordered: 20 - Available qty: 10 - Backordered qty: 10 - Second cart item: - Qty ordered: 20 - Available qty: 0 - Backordered qty: 20 - Total ordered qty: 40 - Total available qty deducted: 10 - Total backordered qty: 30 - Admin order view should also reflect correct split per item. ### Actual result (*) - First cart item shows: - Remaining / backordered qty = 10 - Second cart item shows: - Backordered qty = 30 - Instead of splitting based on remaining salable qty in stock, Magento assigns incorrect backorder calculation across cart items. - After order placement, admin order item quantities also show incorrect backorder distribution. <img width="1353" height="342" alt="Image" src="https://github.com/user-attachments/assets/554db75c-4ed8-4f5a-bef9-92b5adffd75c" />
Preconditions (*)
Steps to reproduce (*)
Expected result (*)
Cart should show correct stock/backorder distribution per line item:
Actual result (*)