The Aging Report found in Reports > Accounting > Aging Report is a historical reference that displays the list of active invoices and balances that existed at the end of the day on any given day. At approximately midnight each night, the database captures what is essentially a screenshot of the list of active invoices and their balances and stores that information. At any time a practice can search a previous date in the Aging Report to view the invoice list and aging balances as they existed on that day.
Unfortunately during the automated process for capturing these screen shots on 10/8/2019 and 2/10/2020 an error occurred and the process did not complete. For many practices this screen shot will not exist for 10/8/2019 or 2/10/2020. No data was lost, it is simply a missing screen shot.