xmlns attribute name duplicated when transforming HL7 message to XML

As part of a process to generate FHIR XML bundles from HL7 messages, I have a subtransform transforming segments of an MDM_T02 message into a section of XML (EnsLib.EDI.XML.Document). So far this has worked well although I've encountered strange behaviour when making use of an xmlns attribute, whereby the attribute's name is duplicated despite the schema and DTL editor displaying it correctly.

Here's a snippet of the div.xmlns definition from the XSD schema used

Has anyone else encountered this? Any help is much appreciated