Issue with Details in Inventory Receipt API with 2 step transfer (Attributes not updated for line items)

When trying to add this record with the TransferNbr in the request payload, The line items data is not including my custom fields. I have extended the endpoints to include newly added custom fields and they are working fine when I try to add the standalone Inventory Receipt, but they are not populated when I try to add TransferNbr and add the line items, the custom fields are not populated.