diff --git a/mod/assign/feedback/comments/locallib.php b/mod/assign/feedback/comments/locallib.php
index 07c83bc28f8..6bd4466e2ce 100644
--- a/mod/assign/feedback/comments/locallib.php
+++ b/mod/assign/feedback/comments/locallib.php
@@ -348,7 +348,11 @@ class assign_feedback_comments extends assign_feedback_plugin {
             $feedbackcomments = $this->get_feedback_comments($grade->id);
         }
 
-        if ($feedbackcomments && !empty($feedbackcomments->commenttext)) {
+        // Check first for data from last form submission in case grading validation failed.
+        if (!empty($data->assignfeedbackcomments_editor['text'])) {
+            $data->assignfeedbackcomments = $data->assignfeedbackcomments_editor['text'];
+            $data->assignfeedbackcommentsformat = $data->assignfeedbackcomments_editor['format'];
+        } else if ($feedbackcomments && !empty($feedbackcomments->commenttext)) {
             $data->assignfeedbackcomments = $feedbackcomments->commenttext;
             $data->assignfeedbackcommentsformat = $feedbackcomments->commentformat;
         } else {