Contrive a scenario where the  mod_forum\task\cron_task runs before another task that generates logged events like core\task\completion_regular_task , e.g.: Prevent automatic execution of cron for this test. Set $CFG->maxeditingtime to 1 in config.php to avoid wasting your time waiting for forum posts to be sent. Establish a course with two students. Students should have their preferences set to receive individual forum post notifications and read tracking. Add a Forum with forced subscription. Add a Page resource, set its activity completion condition to be manual. Configure course completion to be dependent on the Page resource. Log in as the first student and mark the Page resource as complete. At a command line, execute admin/cli/cron.php  to prime the course completion process. The second cron invocation to come triggers the course completion event. Log in as the second student and post in the Forum. At a command line, run the cron script. Verify in the output that the mod_forum\task\cron_task task was run. Verify that the core\task\completion_regular_task task was run also and after forum. As a teacher/admin, view the course log. Observe the 'User full name' column for a 'course completed' event affecting the first student. Without the fix it ought to show a non-admin user, hopefully the second student used above. With the fix it will show the site admin user.