xQuery question

Been wrapping my head around this for too long and need a fresh set of eyes :)

Simple case:

select xmlquery('xquery version "1.0"; copy $d := . modify insert nodes $parent/$child as last into $d/root return $d ' passing xmltype('<root></root>'), xmltype('<child>123</child>') as "child", xmltype('<parent>456</parent>') as "parent" returning content ) as x from dual;

What I'd expect:

<root>
<parent>

  <child>123</child>
</parent>
</root>

But it's ignoring the parent and giving me only:

<root>

  <child>123</child>
</root>

I can't see why, but I must be missing something obvious.

Stefan

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