Issue with coupons

Hello,
With version 1.8.8, coupons are not applied correctly.
When applying a coupon, the price of the product changes.

For example:
× 1 €447.00
Subtotal: €447.00
Total: €447.00 (includes €77.58 VAT 21%)
When applying a 10% discount coupon, it changes to this:
× 1 €497.51
Subtotal: €497.51
Discount: -€9.10
Total: €437.90 (includes €84.77 VAT 21%)

Thank you and best regards.