Coupon not reflecting in the unbilled charges

Scope

Coupon not reflecting in the unbilled charges for the subscription

When a coupon is applied and invoicing is not generated immediately (taken to unbilled charge), the discount will not be shown in the unbilled charge until the invoice is generated.

The coupon is added during subscription creation

Still the Total unbilled charges doesn't include the 20% discount

When the invoice is previewed/generated the coupon will be applied to it.