Why ShipStation shows __section_store_cart_managed as a customer note
If your ShipStation orders show __section_store_cart_managed: true where the customer's own message should be, nothing is wrong with the order. It is in the right place in Shopify, and ShipStation is moving it.
What is actually happening
Our cart drawer tags each order it handles with an order attribute. Shopify keeps attributes and customer notes in two separate fields.
Open the order in Shopify admin and you will see it filed correctly under Additional details, with Notes showing "No notes from customer".

ShipStation pulls both fields and merges them into one box called Note From Buyer. That is where the tag turns up looking like something your customer typed.

Does it affect anything?
No. It does not change the order, the items, the shipping, or the label.
Can you turn it off?
Not from our side. The attribute is what lets the drawer manage the cart correctly, and it is already stored in the field Shopify intends for it.
The merge happens inside ShipStation, so anything that changes it has to be done there. This is not specific to us: ShipStation combines order attributes from every app into that same field, and it has worked this way for years. If it gets in the way of your packing slips, ShipStation support can tell you what your account allows.
Related
- Bundle Sections Conflict with Currency Converter apps, another app reading our data differently
- Add-ons or Upsell Section Not Showing (or Not Adding to Cart)
- Translate bundles and cart drawer text