Ocerra has auto-duplicate invoice detection feature. It works based on the invoice number.
If there are two invoices with the same invoice number, it will highlight both documents:
Important: We recommend reviewing duplicates thoroughly. If this is a genuine duplicate, click the archive button to avoid double payment when exporting to your system.
When you open up an invoice, next to the invoice number, you will see an option to review this invoice duplicate. If you click on it, it will open in a new tab, you can review and archive if required:
You should also be taking other precautions to prevent duplicated payments.