A vendor invoice is entered with terms of Net 30 with a discount of 2% before 10 days. A credit note is issued for the invoice, and the user needs to take the 2% discount from the credit note as well.
Terms cannot be set for credit notes. They are either aged as current, or by their date, and this option is set in AP Setup / Options on the Processing Tab. When a credit note (or debit note) is entered in AR, the Terms tab disappears.
The workaround then, is to enter the credit note for the net amount. However, if the user needs to see the full amount and the discount separately, enter the credit note for the full amount and then make an adjustment to that credit note for the discounted amount.