• Navigate to a course on 3.3.
• Login as a teacher or admin.
• Create a test student and enroll the student in this course.
• Create an assignment and enable completion tracking for the assignment.
• Set the completion requirement to "Students can manually mark the activity as completed".
• Log in as the student and mark the activity as completed.
• As the teacher or admin, navigate to the activity settings and expand the activity completion menu. You will see the following warning message appear: https://www.screencast.com/t/2re6C8Vp
• Still logged in as the teacher or admin, navigate to Course Admin > Course Completion > Bulk edit activity completion.
• Select the activity you used for testing and click edit.

When editing the completion settings for an individual assignment, a teacher is first warned that activity has already been marked and must choose to unlock the completion settings before making any changes:
https://www.screencast.com/t/2re6C8Vp
However, if the update to completion settings is done via the Bulk activity completion settings, no warning appears and completion is still deleted for any selected activity or resource. You can see this in action in the following video:
https://www.screencast.com/t/nLIeK0MXWlZf
There needs to be a similar warning in the bulk activity completion settings to alert teachers of the danger to updating completion, like:

Updating completion settings will erase existing completion data and may cause confusion. Thus completion settings should not be changed here unless absolutely necessary.

The solution for this can be done adding the following:

• *course/templates/editbulkactivitycompletion.mustache
  *Adding, after the {form}: 

<p>{{#str}}bulkcompletionwarningtext, completion{{/str}}</p>

• lang/en/completion.php**Adding, on line 51:

  $string['bulkcompletionwarningtext'] = '<strong>Updating completion settings will erase existing completion data and may cause confusion. Thus completion settings should not be changed here unless absolutely necessary.</strong>';

Can this be done somehow?

Thanks.