An eXtender window is linked to SOP Entry, however the information is disappearing when the document is transferred to a different document type.
eXtender has code built into it that will transfer the information, however the link must be made correctly. If your information is linked to the SOP Header, the only field you can link on is SOP Number. If the link is made on any other field, the information will not transfer. If your information is linked to the SOP Line Items, the linking fields should be SOP Number and Line Item Sequence.