diff --git a/public/main/exercise/exercise.class.php b/public/main/exercise/exercise.class.php
index 2a53ae8c7f..054b5c9f91 100644
--- a/public/main/exercise/exercise.class.php
+++ b/public/main/exercise/exercise.class.php
@@ -3,6 +3,7 @@
 /* For licensing terms, see /license.txt */
 
 use Chamilo\CoreBundle\Component\Utils\ChamiloApi;
+use Chamilo\CoreBundle\Component\Utils\ToolIcon;
 use Chamilo\CoreBundle\Entity\GradebookLink;
 use Chamilo\CoreBundle\Entity\TrackEExercise;
 use Chamilo\CoreBundle\Entity\TrackEExerciseConfirmation;
diff --git a/src/CourseBundle/Entity/CQuiz.php b/src/CourseBundle/Entity/CQuiz.php
index 36e63e4fda..be538096c1 100644
--- a/src/CourseBundle/Entity/CQuiz.php
+++ b/src/CourseBundle/Entity/CQuiz.php
@@ -187,7 +187,9 @@ class CQuiz extends AbstractResource implements ResourceInterface, ResourceShowC
      */
     public function getQuestions(): ArrayCollection
     {
-        return $this->questions;
+        return $this->questions instanceof ArrayCollection ?
+            $this->questions :
+            new ArrayCollection($this->questions->toArray());
     }
 
     public function setTitle(string $title): self
@@ -618,7 +620,9 @@ class CQuiz extends AbstractResource implements ResourceInterface, ResourceShowC
      */
     public function getQuestionsCategories(): ArrayCollection
     {
-        return $this->questionsCategories;
+        return $this->questionsCategories instanceof ArrayCollection ?
+            $this->questionsCategories :
+            new ArrayCollection($this->questionsCategories->toArray());
     }
 
     public function getResourceIdentifier(): int|Uuid