As admin: Ensure the Forum module setting "Manual message read marking" is disabled. In a course, create a force-subscribed forum. Enrol a student user in the course. Configure the student user with forum digest type "complete", read tracking "yes", and "mark post as read" when sending post notifications. Create a post in the forum with "no editing-time delay" set. Log in as the student, view the forum and observe the unread post. Run: php admin/tool/task/cli/schedule_task.php --execute='mod_forum\task\cron_task' Observe the task output reads "Queued 1 digests". Fudge the queued adhoc tasks via SQL so they can be executed immediately: UPDATE mdl_task_adhoc SET nextruntime=1 Run: php admin/tool/task/cli/adhoc_task.php --execute Observe that the mod_forum\task\send_user_digests task ran. While still logged in as the student, reload the same forum page. Before fix: observe the same unread post remains. After fix: observe no unread posts are shown. Confirm the alternative behaviour. As admin: Ensure the Forum module setting "Manual message read marking" is enabled. Execute steps 2 through 9 from above. While still logged in as the student, reload the same forum page. Before fix: observe no unread posts are shown. After fix: observe the same unread post remains.