We transfer the data from the warehouse via the Shopify API. The API does not report any errors. However, customers complain that there is no shipment data and the order is not in the "fulfilled" status.
We always getting 201 Created back from the API. The problems have existed for about 2 months and have arisen by themselves. The API has not been changed in the program logic for a longer time. Not all orders are affected, but sporadically individual orders without a recognizable pattern.
Does anyone have any idea how to narrow down the problem?