SQL Server XML Data Type and QUOTED_IDENTIFIER

Question

Can anyone provide insight into this?

I've developed an import process using an XML data type. After the data is inserted in to a table by the import sProc I run another procedures to update another table with the imported table.

The update procedure throws an exception if it is created with SET QUOTED_IDENTIFIER OFF. I'd like to understand why that is happening.

Here's the code:

DECLARE @xmlRecords XML
SET     @xmlRecords = (SELECT importedXML FROM importTable WHERE importId = @lastImportId)

UPDATE  o
SET     o.ReferralCode = import.refCode
FROM    (
            SELECT  records.record.value('(@orderId)[1]', 'INT') AS orderId, 
                    records.record.value('(@refCode)[1]', 'VARCHAR(15)') AS refCode
            FROM    @xmlRecords.nodes('/records/record') records(record)
            ) import 
            INNER JOIN tblOrder o ON import.OrderId = o.orderId

I'm assuming it has to do with the quoted datatypes ('VARCHAR(15)') or the xml query path elements ('/records/record').

Thanks for any insight you can provide.