diff --git a/mod/assignment/lib.php b/mod/assignment/lib.php
index 6c8dbba..336282a 100644
--- a/mod/assignment/lib.php
+++ b/mod/assignment/lib.php
@@ -604,7 +604,7 @@ class assignment_base {
 
                         //add to log only if updating
                         add_to_log($this->course->id, 'assignment', 'update grades',
-                                   'submissions.php?id='.$this->assignment->id.'&user='.$submission->userid,
+                                   'submissions.php?id='.$this->cm->id.'&user='.$submission->userid,
                                    $submission->userid, $this->cm->id);
                     }
 
@@ -1429,7 +1429,7 @@ class assignment_base {
             $this->update_grade($submission);
 
             add_to_log($this->course->id, 'assignment', 'update grades',
-                       'submissions.php?id='.$this->assignment->id.'&user='.$feedback->userid, $feedback->userid, $this->cm->id);
+                       'submissions.php?id='.$this->cm->id.'&user='.$feedback->userid, $feedback->userid, $this->cm->id);
         }
 
         return $submission;
diff --git a/mod/assignment/type/offline/assignment.class.php b/mod/assignment/type/offline/assignment.class.php
index 464b5d2..d79aab8 100644
--- a/mod/assignment/type/offline/assignment.class.php
+++ b/mod/assignment/type/offline/assignment.class.php
@@ -93,7 +93,7 @@ class assignment_offline extends assignment_base {
             $this->update_grade($submission);
 
             add_to_log($this->course->id, 'assignment', 'update grades',
-                       'submissions.php?id='.$this->assignment->id.'&user='.$feedback->userid, $feedback->userid, $this->cm->id);
+                       'submissions.php?id='.$this->cm->id.'&user='.$feedback->userid, $feedback->userid, $this->cm->id);
         }
 
         return $submission;