Amazon takes 10-60 minutes to receive updates even though Codisto sends messages to Amazon immediately. This includes inventory edits from Shopify to Amazon (e.g. more goods received).. Because of this, it is possible for a merchant to oversell using this channel. Amazon can process a sale if the product has run out of stock in the past 10 minutes. 

If you have fast selling inventory, consider using the Quantity Buffer option in the inventory field inside Amazon by Codisto.

This can be done in Single Edit Mode or Bulk Edit Mode:

In Single Edit Mode click on the item and scroll down to Inventory as per below.

In Bulk Edit Mode click on Add Fields, select Offer Fields and Inventory, scroll to the right and locate the Inventory column as per below.