Product added to "Checkout" through API is not persisting
Hello API team,
I have developed a solution for a client. On checkout page our script sends "checkout id" to our back end, and then our back end makes a POST request to API to add a specific product to checkout.
This functionality used to work. However it started not working. I inspected situation and concluded this is happening. When we send the request it indeed adds the product to "checkout". However when ever anything else is updated, email, shipment method etc. the product is removed.
I am unable to fix this issue. Can someone assist me or point me to a document which would explain why some products would not persist in "checkout" entity.