Sales Report coupon value incorrect

[rednaxela]

Joomla 3.10.11
VirtueMart 4.0.6 10690

The sales report shows incorrect values for coupon amounts. The coupon amount is multiplied by the number of different products sold.

If you sell 2 different products with a total discount of 10€ the sales report shows an incorrect discount of 20€
If you sell 1 product twice (Quantity 2) with a total discount of 10€ the sales report shows the correct discount of 10€


Does anyone know how to fix this?