Segmentation fault (access null pointer) in ext/libxml/libxml.c #14698

<?php
  $dom = new DOMDocument;
  $dom->loadHTML('<span title=""y">x</span><span title=""z">x</span>');
  $html = simplexml_import_dom($dom);
  foreach ($html->body->span as $obj) {
  }
  $script1_dataflow = $html;
  $array = ['foo'];
  foreach ($array as $key => &$value) {
    unset($script1_dataflow[$key]);
  }