The purchase order that came back
A retailer resent an order we had already shipped. Every field said it was new.
In September 2026 a department-store order arrived by EDI on a Monday and shipped Tuesday. The same purchase order came back the following Monday as a brand-new ApparelMagic order. The customer PO number was identical. The EDI reference had the same digits with two letters added in front.
Our automation approved its credit, allocated it, picked it and invoiced it. The second label was stopped by hand.
Why nothing caught it
A resend looks pristine. Credit Pending, nothing allocated, nothing picked, order open. Those are exactly the fields that say an order is ready to work. Every readiness check passed because the order really was untouched. It was also a duplicate.
The check we added
Before working any order from that retailer, the job compares it against every order from the same customer in the last ten days, on two keys:
- the EDI reference reduced to its digits, so any prefix collides
- the customer PO, whole
The window has to include closed orders. The original had already shipped and closed by the time the resend arrived, so a search of open orders would never find it. That is the easy mistake, and the reason this check needs the pagination fixes from the last note.
It fails closed
If the job cannot read the full ten-day window, it processes nothing and the morning email names the orders it left alone. That choice is about cost. A pick-up order delayed by a day is a phone call. A second label on goods already shipped is a chargeback and a credit memo.
We were tempted three times to soften this, and each time it would have reopened the hole: warning about a short window in an email sent after the invoices were raised, skipping rows whose dates could not be read, and treating a page cap of zero as an empty window. Each looked reasonable in review. Each was a way to fail open.
What it does not do
It writes nothing. No void and no cancel in either system. Only a person cancels a retailer's order. The job's job is to stop and say why.
We fixed the invoice, of course. But that one order is why these rules exist.
If your EDI orders flow straight into allocation, it is worth checking what happens on a resend. Happy to compare notes.