Symptoms
An order was placed with PlaceOrderAndAuthorize_API method, with parameter SalesBranchID set to some existing value. As a result, order was created but without sales branch id.
Cause
The reason is the bug with id #PBA-77067 ("PlaceOrderAndAuthorize_API does not set SalesBranchID if passed without SalesPersonID").
Resolution
Add a parameter SalesPersonID to the API call.