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 43474a7d..a1987bb9 100644
--- a/question_types/quiz_multichoice/src/Plugin/quiz/QuizQuestion/MultichoiceResponse.php
+++ b/question_types/quiz_multichoice/src/Plugin/quiz/QuizQuestion/MultichoiceResponse.php
@@ -139,11 +139,11 @@ class MultichoiceResponse extends QuizResultAnswer {
           'chosen' => $chosen,
         ],
         'data' => [
-          'choice' => check_markup($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' => $icon_correct,
           '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' => $correct ? QuizUtil::icon('should') : ($simple_scoring ? QuizUtil::icon('should-not') : ''),
           'quiz_feedback' => 'Quiz feedback',