foreach ($elements as $element)
{
...
}

$jform = new JForm('testform');
$jform->load(<<<'XML'
<form>
  <fields name="A">
    <field name="fielda"/>
    <fields name="B">
      <field name="fieldab"/>
    </fields>
  </fields>
</form>
XML
);
$field = $jform->findField('fieldab','A'); // should return false, but returns whole <fields name="A"> element.
print ($field? $field->asXML()."\n": "false")."\n";

$jform->load(<<<'XML'
<form>
<fields name="A">
  <field name="fieldab"/>
</fields>
</form>
XML
,true); // should add a new <field name="fieldab"/> element to the <fields name="A"> element, instead deletes the whole original <fields name="A"> element and adds the <field> at the "top" level.
print $jform->getxml()->asXML();