Lately we are seeing a lot of our apps on Shopify sending information like discount codes used or "how did you hear about us" answers that are now showing up in the "notes to seller" section. So normally we know a customer left us a note if the box in shipstation is blue but now any stackable discount code thats used or answer that is submitted by the customer shows up in this "notes to seller" box. A shopify agent reached out to shipstation on our behalf and shipstation said to submit a request here. To help with the technical details I will include what the shopify agent recommended
"I understand that you don't have any insight on how Shopify sends information to Shipstation. Unfortunately, our scope of support ends at the use of API's. That being said, based on my experience, Shipstation must be using our [**Orders API**](https://shopify.dev/api/liquid/objects/order?shpxid=fc55ed5b-7445-43AC-4648-360885D25571#order-attri...) to draw information from the order page. This API gives Shipstation access to several **Order Objects** such as **order.attribute**, which you could leave out of the data pull to avoid getting this field into Shipstation. This order object is one of many that your developers can leave to prevent importing the additional details field."
Hope this helps and is something that can be fixed in the future so that actual notes from customers do not continue to get buried in random system generated notes that are not of value to us. Thank you!