I am also facing the same problem in Moodle 3.4
Our course content is a PDF that opens in a new window. We want the activity completion to automatically mark as complete once the student opens it. Currently the student has to reload the page in order to see the tick mark updated. Is there a workaround for this?
Previously we have create course contents using 'Page' or even assignments or quizzes, they do not face this problem because the moodle moves to assignment/quiz page before coming back to the course page and updating the activity completion.
Can someone please advice?