diff --git a/mod/quiz/classes/quiz_attempt.php b/mod/quiz/classes/quiz_attempt.php
index aacf15a5256..d70ca51543d 100644
--- a/mod/quiz/classes/quiz_attempt.php
+++ b/mod/quiz/classes/quiz_attempt.php
@@ -2323,6 +2323,9 @@ class quiz_attempt {
     public function get_number_of_unanswered_questions(): int {
         $totalunanswered = 0;
         foreach ($this->get_slots() as $slot) {
+            if (!$this->is_real_question($slot)) {
+                continue;
+            }
             $questionstate = $this->get_question_state($slot);
             if ($questionstate == question_state::$todo || $questionstate == question_state::$invalid) {
                 $totalunanswered++;
diff --git a/mod/quiz/tests/attempt_walkthrough_test.php b/mod/quiz/tests/attempt_walkthrough_test.php
index c2a294f33ff..6fec8add16a 100644
--- a/mod/quiz/tests/attempt_walkthrough_test.php
+++ b/mod/quiz/tests/attempt_walkthrough_test.php
@@ -58,11 +58,13 @@ class attempt_walkthrough_test extends \advanced_testcase {
         $saq = $questiongenerator->create_question('shortanswer', null, ['category' => $cat->id]);
         $numq = $questiongenerator->create_question('numerical', null, ['category' => $cat->id]);
         $matchq = $questiongenerator->create_question('match', null, ['category' => $cat->id]);
+        $description = $questiongenerator->create_question('description', null, ['category' => $cat->id]);
 
         // Add them to the quiz.
         quiz_add_quiz_question($saq->id, $quiz);
         quiz_add_quiz_question($numq->id, $quiz);
         quiz_add_quiz_question($matchq->id, $quiz);
+        quiz_add_quiz_question($description->id, $quiz);
 
         // Make a user to do the quiz.
         $user1 = $this->getDataGenerator()->create_user();
@@ -77,7 +79,7 @@ class attempt_walkthrough_test extends \advanced_testcase {
         $attempt = quiz_create_attempt($quizobj, 1, false, $timenow, false, $user1->id);
 
         quiz_start_new_attempt($quizobj, $quba, $attempt, 1, $timenow);
-        $this->assertEquals('1,2,3,0', $attempt->layout);
+        $this->assertEquals('1,2,3,4,0', $attempt->layout);
 
         quiz_attempt_save_started($quizobj, $quba, $attempt);