To determine the status of items that have been mapped correctly or not, in the 'SKU Mapping' section, a seller can check the mapping of items between the Amazon FBA SKU and the Shopify SKU.
If the Shopify SKU is not mapped to the Amazon FBA SKU, it will be displayed in the image below. You can then click the 'Update' button to map the SKU.
SKU Mapping (Shopify to Amazon)
Once your Shopify SKU is mapped to the Amazon FBA SKU, it will appear as shown in the attached image.