StagingPro is designed to create staging environments and not (at least at this stage) a way of pushing data to production. One of the challenges faced is that item indexes are changed for each BigCommerce store and this includes the order id.
This will not impact the work you can do in your environment. StagingPro has still kept the relationships between records intact and the same amount of data has been moved, so none of your testings will be affected.
StagingPro will soon be rolling out a new feature which will display the original order id from the source environment in the Order Comments section of the destination storeNo, during StagingPro migrations from the source store to the destination store, we have no control of the increment ID’s assigned by BigCommerce’s systems when the data hits the target store. Which is why, as an example, products must use SKU as the point of reference, not product ‘increment’ ID which is BigCommerce auto generated.