In a Magento 1.9 Store was the problem, that it was "suddenly" no longer possible with Gift Certificates (Extension “Gift Card"From Magestore) to pay. The coupons were redeemed though and however, the sum of the value of the voucher taken off the order total was unchanged. Thus, the customer would have paid on the one hand with his promo and additionally pay the full amount (o.ä.) have to.
After some investigation it turned out, or that it conflicts with the extension "Refund Product". pledged property was of conlabz.
Once this extension was disabled, the voucher amount was deducted from the purchase price and reported correctly.
Since we no longer needed the extension, helped this out already, so we were looking for no other solution to the conflict. Should this happen, It is noted here.
If someone else face the same problem, may help him but this notice. I would be glad, if someone finds the solution thus faster and even us participate in the solution can.
Used in Magento Version 1.9 Comments? Additions? Notes? Gladly!by