The net amount of the items is posted into stock. In addition, the amount of the discount is posted separately. We want not to have this discount posting. As the net amount is already posted an additional posting of the discount is not needed/allowed.

-Created a purchase order with the multiple items and given the percentage in the "Discount percent" in the PO line then posted the invoice and check the posted voucher transactions.

Do not have a setup for the purchase discount in the posting profile

This additional posting would just make sense if the but amount would be posted.