Hi Mike,

The first digit is the document type (which is an invoice or adjustment, as you correctly indicated). The rest is the document number - does this have the same 'RC' number. When posting any PO document, you can over-ride any part of the number, including the prefix. Thus it is possible to have posted an invoice with any characters in the document.

Ensure that the company setup didn't get acidentally changed (Order receipts defaults) - not likely but have to check everything.

We're not aware of any reasons why the wrong document number/prefix would have been applied to an invoice.