diff --git a/question_types/quiz_multichoice/src/Plugin/quiz/QuizQuestion/MultichoiceResponse.php b/question_types/quiz_multichoice/src/Plugin/quiz/QuizQuestion/MultichoiceResponse.php
index b733e7d3..b77ff004 100644
--- a/question_types/quiz_multichoice/src/Plugin/quiz/QuizQuestion/MultichoiceResponse.php
+++ b/question_types/quiz_multichoice/src/Plugin/quiz/QuizQuestion/MultichoiceResponse.php
@@ -121,11 +121,11 @@ class MultichoiceResponse extends QuizResultAnswer {
       $chosen_feedback = $alternative->{"multichoice_feedback_{$not}chosen"};
 
       $data[] = [
-        'choice' => check_markup($alternative->multichoice_answer->value, $alternative->multichoice_answer->format),
+        'choice' => check_markup((string) $alternative->multichoice_answer->value, $alternative->multichoice_answer->format),
         'attempt' => $chosen ? QuizUtil::icon('selected') : '',
         'correct' => $chosen ? $alternative->multichoice_score_chosen->value > 0 ? QuizUtil::icon('correct') : QuizUtil::icon('incorrect') : '',
         'score' => (int) $alternative->{"multichoice_score_{$not}chosen"}->value,
-        'answer_feedback' => check_markup($chosen_feedback->value, $chosen_feedback->format),
+        'answer_feedback' => check_markup((string) $chosen_feedback->value, $chosen_feedback->format),
         'question_feedback' => 'Question feedback',
         'solution' => $alternative->multichoice_score_chosen->value > 0 ? QuizUtil::icon('should') : ($simple_scoring ? QuizUtil::icon('should-not') : ''),
         'quiz_feedback' => "Quiz feedback",