When does AutoInvoice purge processed data?

If the Purge interface tables Receivables system option is enabled, then the Purge AutoInvoice Interface Data process runs automatically after AutoInvoice has validated and transferred data to Receivables. The process purges all processed lines interfaced from all sources.

If the Purge interface tables Receivables system option isn't enabled, then you must submit the Purge AutoInvoice Interface Data process manually to purge temporary data. Submitting the process manually purges both processed and unprocessed lines--with the exception of unprocessed lines interfaced from Oracle Fusion Cloud upstream systems: Order Management, Project Management, Subscriptions.

You can't purge unprocessed lines interfaced from Oracle Fusion Cloud upstream systems under any circumstances.