When changing the owner of an IB record, a warranty is created in the wrong org. Why?

I am testing a program that calls csi_item_instance.update_item_instance to change the owner of an IB record.  The item in the IB record has a warranty item associated to it, so there is an existing warranty contract.  This existing warranty contract is in org_id "A", let's say.  When the API has finished changing the owner, I notice that the existing warranty contract has been terminated, and a new one has been created.  So far, so good.  The only problem is that the new warranty contract has been created in org_id "B".  The wrong org.