Stand alone sales A/R return

Hello Experts,

Why system did not pass a journal entry in case of stand alone sale A/R return document.

We have a chain

Sales Order --> A/R Delivery --> A/R Invoice.

Because invoice got closed. We punched a stand alone return document and then punched A/R Credit Memo.

In the return document there is no journal entry passed so the item cost in the audit report is zero.

Thanks in advance.