If Shopify orders are created multiple times in PlentyONE, this is usually because the external order ID (External Order ID) is subsequently changed in the system by an external process or a REST API script.

Cause of the problem

PlentyONE uses the external order ID provided by Shopify to assign later order updates (e.g. after waiting states expire on marketplaces) to the existing order. If this ID is changed or overwritten by an external script, a third-party tool, or a manual REST API call (e.g. when adjusting prices), PlentyONE can no longer assign the incoming reconciliation and creates the order again as a duplicate.

Step-by-step guide to troubleshooting

1. Check whether external REST API scripts or third-party tools automatically process orders after import (e.g. calls to the route /rest/orders/).

2. Ensure that in API payloads for price or position adjustments, the field for the external order ID is not changed or overwritten.

3. Navigate in the PlentyONE backend to Orders » Edit Orders and compare the external order ID of the duplicate with the original ID in Shopify.

4. Correct the external API process so that the original Shopify order ID remains unchanged when updating order data.