Okay let me explain how your microflow is working on that case. First you do a retrieve and then you obtain I assume one order, then you create a new object and later on you add it to the list so that's why you see that the OrderStoredList has two elements. After the loop you do another retrieve and then you see a list with only one element. This is behaviour is correct. You need to understand that all database operations are done at the end of the transaction (Microflow) so even when you see your commit before the retrieve this is not being until the end of the your microflow so when you do the retrieve, your new object is not in the db yet.
If you have any other question, please let me know.
You can create a empty list of OrderStored and add each itarator on this. After this actions is complete, you can commit this list and then you'll have all objects on this entity.