Steps to Reproduce the Problem:

1. Create a Course:

• • Create a course named "C1".

1. Enroll Students:

• • Enroll two students: "S1" and "S2".

1. Add Activities:

• • Add a "Lesson" activity named "L1".
    • Configure "L1" for automatic completion, using the "view" criteria for example, so that simply viewing the lesson completes it.
  • Duplicate L1 and name it L2

1. Configure Course Completion:

• • Go to "More > Course Completion".
  • Add two completion criteria (AND):
    • "Activity completion L1".
    • "Activity completion L1".

1. Student S1 Completes the Course:

• • Log in as "S1" in a separate browser (private mode recommended).
  • Access course "C1".
  • Complete activities "L1" and "L2".
  • Verify that course "C1" shows 100% completion for "S1".

1. Admin Removes Activity L1:

• • Log in as administrator.
  • Access course "C1".
  • Delete activity "L1" from the course. Do not use the "Unlock completion settings and delete user completion data" option on the course completion settings page.

1. Verify Course Completion for S1:

• • Verify that student S1 remains with the course completed.

1. Student S2 Completes the Remaining Activity:

• • Log in as student S2.
  • Complete activity L2.
  • Verify the course status for student S2.

Expected Result: (check report/completion/index.php?course=IDDOCURSO)

• Student "S2" should should have Course Complete in the the course Completion Report (since they completed Q1). 

Actual Result:

• Student "S2" is shown as having not completed the course

Background

In my case, I had configured a 'Lesson' module with specific completion settings, so that the student could meet the criteria and have this module marked as completed by Moodle. This worked perfectly. This same 'Lesson' module was associated with the course completion settings as a criterion to be met for the student to have the course 100% completed.

I needed to delete this 'Lesson' module as it was no longer necessary. I simply deleted it from the course, not from the course completion settings page, where after deletion, this module was no longer reflected.

Some time later, in a support request, I had a case of a student who met all our course completion criteria, but Moodle did not register the course completion for the student.

After thinking that simply deleting the 'Lesson' module from the course where it was part of the course completion settings would be sufficient, I realized that I should validate it by doing the test to confirm.

Remember that I only deleted the module within the course and did not use the option on the 'course completion' settings page where there is a button called 'Unlock completion settings and delete user completion data'.

After using the button, I saw Moodle minutes later registering the course completion for the student as expected.

I'm not sure if this affects other versions, but I'm leaving this here in case it helps.