Issue with Seeded Order Management API

Dear Experts,

I am using the seeded API

WSH_DELIVERIES_PUB.DELIVERY_ACTION  in my concurrent request. This API does the Ship Confirm and also changes the line status from Picked to Ship Confirm

I have a test where in the weight of the Item is Null. So a Null value is passed. When I do a ship confrim from the system it gives me a warning and on clicking Ok it continues with the processing and the order is shipped. However when I do the same test by calling the API from the concurrent program the return status is warning and it does no further processing. The order is not shipped and the line status is still in Picked status.