I am having issues with the new json-to-xm functions with a copy clause.

I would expect the following query to work:
let $json := '{"age":23,"name":"Bob"}'
return
copy $out := json-to-xml($json)
modify delete node $out//*[@key='age']
return xml-to-json($out)

Instead I get an error when calling xml-to-json: [FOJS0006] Element 'map' has invalid namespace: ''.

It appears the copy clause is dropping the namespace on the map object. Is this something I must manually prevent or a bug?

Thanks for all your time.

- James