From the PO confirmation log, noticed a few POs created outside D365 (migrated from Oracle) are within the PO confirmation log? How did this happened?

From the PO confirmation log, noticed a few POs created outside D365 (migrated from Oracle) are within the PO confirmation log? How did this happened?
Hi OHZ,
Is there any person who was involved in the migration who can help you? On this forum we don't know the contents of your orders or how it has been imported or entered and if a confirmation was posted or simulated with e.g. custom coding.