diff --git a/qmlti/src/lti/model/staff.php b/qmlti/src/lti/model/staff.php
index 06a8d52..d09b9e7 100644
--- a/qmlti/src/lti/model/staff.php
+++ b/qmlti/src/lti/model/staff.php
@@ -377,7 +377,7 @@ function getAssessments() {
     if ($this->ok && (($assessments = get_assessment_list()) === FALSE)) {
       $assessments = array();
     } else {
-      $filtered_assessments = array_filter($assessments, array($this, 'filterDisabledForExternal'));
+      $filtered_assessments = array_values(array_filter($assessments, array($this, 'filterDisabledForExternal')));
     }
     return $filtered_assessments;
   }