when trying to duplicate a quiz
debug mode max DEVELOPER
if the course's question bank contains Matching questions, error:
even if the quiz being duplicated does NOT contain any matching questions!
example with course containing just one matching question:
// question: 43 name: match countries and capitals
::match countries and capitals::[html]<p>match countries and capitals</p>{
=<p>France</p> -> Paris
=<p>the US</p>\n<p> </p> -> Washington
=<p>Italy</p>\n<p> </p> -> Roma
}

------------------
error/error_question_match_sub_missing_in_db

More information about this error
Debug info:
Error code: error_question_match_sub_missing_in_db
$a contents: stdClass Object
(
[id] => 8
[code] => 407836914
[questiontext] => <p>the US</p>
<p> </p>
[questiontextformat] => 1
[answertext] => Washington
)
Stack trace:

line 144 of \question\type\match\backup\moodle2\restore_qtype_match_plugin.class.php: restore_step_exception thrown
line 131 of \backup\util\plan\restore_structure_step.class.php: call to restore_qtype_match_plugin->process_match()
line 103 of \backup\util\helper\restore_structure_parser_processor.class.php: call to restore_structure_step->process()
line 125 of \backup\util\xml\parser\processors\grouped_parser_processor.class.php: call to restore_structure_parser_processor->dispatch_chunk()
line 91 of \backup\util\helper\restore_structure_parser_processor.class.php: call to grouped_parser_processor->postprocess_chunk()
line 148 of \backup\util\xml\parser\processors\simplified_parser_processor.class.php: call to restore_structure_parser_processor->postprocess_chunk()
line 92 of \backup\util\xml\parser\processors\progressive_parser_processor.class.php: call to simplified_parser_processor->process_chunk()
line 169 of \backup\util\xml\parser\progressive_parser.class.php: call to progressive_parser_processor->receive_chunk()
line 253 of \backup\util\xml\parser\progressive_parser.class.php: call to progressive_parser->publish()
line ? of unknownfile: call to progressive_parser->end_tag()
line 158 of \backup\util\xml\parser\progressive_parser.class.php: call to xml_parse()
line 137 of \backup\util\xml\parser\progressive_parser.class.php: call to progressive_parser->parse()
line 105 of \backup\util\plan\restore_structure_step.class.php: call to progressive_parser->process()
line 153 of \backup\util\plan\base_task.class.php: call to restore_structure_step->execute()
line 163 of \backup\util\plan\base_plan.class.php: call to base_task->execute()
line 157 of \backup\util\plan\restore_plan.class.php: call to base_plan->execute()
line 315 of \backup\controller\restore_controller.class.php: call to restore_plan->execute()
line 101 of \course\modduplicate.php: call to restore_controller->execute_plan()