Generally, the celigo documents suggest using any of the refunds flows either from Shopify to NetSuite or NetSuite to Shopify since these flows are working bi-directional and may leads conflicts.
When we run a Shopify- Netsuite refund flow to refund the order from shopify to Netsuite a customer refund record is created in NetSuite. And also a refund ID is also stored in the eTail refund ID field under the eTail subtab. In this case e ‘eTail Order Exported’ will be unchecked.
When we execute the NetSuite-Shopify refund flow to refund the order from NetSuite to Shopify a check box e ‘eTail Order Exported’ will be checked. And the etail refund ID will be empty.
So this can be used as a addition criteria to exclude the orders which is already refunded in Shopify.