Prestashop voucher cart rules remaining balance wrong

[3dron]

If I create a voucher and a user applies it to item and shipping. The remainder of the new voucher does not subtract out the shipping cost.

 

Example:

 

I send out $20 voucher to user.

 

The choose a $15 item with $3 shipping. Total $18. The voucher zeroes out the purchase properly, but the new voucher now has a full $5 amount. Because it did not subtract the shipping cost as well.

 

The voucher should be $2.

 

 

What is the easiest way to go about fixing this?

 

Thanks in advance.

 

3dron