Activity completion FAQ
From Carleton Moodle Docs
What happens when completion conditions are unlocked?
Once you unlock options and then click 'Save changes', all completion information for the activity will be deleted and, if possible, regenerated according to the new settings. See the section 'What happens when you unlock' in Activity completion settings for further details.
Can I change the default completion settings for activities in my course?
Yes. See Activity completion settings for how to do this.
Activity completion status does not change
Check Site administration > Server > Scheduled tasks and the task Calculate completion data. This should ideally be once a minute.