I think there is an issue into function addOrderCoupon()
into file Orders_model.php
. Line: 676 Approx.
Might we have replace:
if (is_array($coupon) AND is_numeric($coupon['discount'])) {
with
if (is_array($coupon) AND is_numeric($coupon['amount'])) {
Because cart_contents['totals']['coupon']
array dosen't have discount
.
Not sure, you have to check it.