diff --git a/mod/assign/lib.php b/mod/assign/lib.php
index d9ded666cd7c2..c3d172e2819e4 100644
--- a/mod/assign/lib.php
+++ b/mod/assign/lib.php
@@ -302,7 +302,7 @@ function assign_update_events($assign, $override = null) {
         // Events module won't show user events when the courseid is nonzero.
         $event->courseid    = ($userid) ? 0 : $assigninstance->course;
         $event->groupid     = $groupid;
-        $event->userid      = $userid;
+        $event->userid      = 0;
         $event->modulename  = 'assign';
         $event->instance    = $assigninstance->id;
         $event->timestart   = $duedate;
@@ -332,6 +332,8 @@ function assign_update_events($assign, $override = null) {
             $params = new stdClass();
             $params->assign = $assigninstance->name;
             $eventname = get_string('overrideusereventname', 'assign', $params);
+            // Only set userid for user override events.
+            $event->userid = $userid;
             // Set user override priority.
             $event->priority = CALENDAR_EVENT_USER_OVERRIDE_PRIORITY;
         } else {
diff --git a/mod/lesson/lib.php b/mod/lesson/lib.php
index 45444fcc958e0..8275fea85749c 100644
--- a/mod/lesson/lib.php
+++ b/mod/lesson/lib.php
@@ -167,7 +167,7 @@ function lesson_update_events($lesson, $override = null) {
         // Events module won't show user events when the courseid is nonzero.
         $event->courseid    = ($userid) ? 0 : $lesson->course;
         $event->groupid     = $groupid;
-        $event->userid      = $userid;
+        $event->userid      = 0;
         $event->modulename  = 'lesson';
         $event->instance    = $lesson->id;
         $event->timestart   = $available;
@@ -200,6 +200,8 @@ function lesson_update_events($lesson, $override = null) {
             $params = new stdClass();
             $params->lesson = $lesson->name;
             $eventname = get_string('overrideusereventname', 'lesson', $params);
+            // Only set userid for user override events.
+            $event->userid = $userid;
             // Set user override priority.
             $event->priority = CALENDAR_EVENT_USER_OVERRIDE_PRIORITY;
         } else {
diff --git a/mod/quiz/lib.php b/mod/quiz/lib.php
index 37873c60a4b9b..ba56c86b4ab85 100644
--- a/mod/quiz/lib.php
+++ b/mod/quiz/lib.php
@@ -1268,7 +1268,7 @@ function quiz_update_events($quiz, $override = null) {
         // Events module won't show user events when the courseid is nonzero.
         $event->courseid    = ($userid) ? 0 : $quiz->course;
         $event->groupid     = $groupid;
-        $event->userid      = $userid;
+        $event->userid      = 0;
         $event->modulename  = 'quiz';
         $event->instance    = $quiz->id;
         $event->timestart   = $timeopen;
@@ -1301,6 +1301,8 @@ function quiz_update_events($quiz, $override = null) {
             $params = new stdClass();
             $params->quiz = $quiz->name;
             $eventname = get_string('overrideusereventname', 'quiz', $params);
+            // Only set userid for override events.
+            $event->userid = $userid;
             // Set user override priority.
             $event->priority = CALENDAR_EVENT_USER_OVERRIDE_PRIORITY;
         } else {