I can confirm your fork fixes the problems we've been having with restore.
I'll post a partial error / stack trace for the benefit of anyone searching for the specific error
Debug info: Incorrect syntax near the keyword 'CONVERT'.
SELECT TOP 1 id FROM mdl_question_order_sub WHERE question = ? AND CONVERT(varchar(32), questiontext) = CONVERT(varchar(32), ?) CONVERT(varchar(32), AND answertext) = CONVERT(varchar(32), ?)
Relevant stack trace:
• line 123 of \question\type\order\backup\moodle2\restore_qtype_order_plugin.class.php: call to moodle_database->get_record_select()
• line 137 of \backup\util\plan\restore_structure_step.class.php: call to restore_qtype_order_plugin->process_order()