Steps to replicate:

1. Create test course
2. Enrol a test student
3. Add the Completion Progress block to the course
4. Create a Label resource and ensure it is set to 'allow students to manually mark as complete'
5. Go back to the course page, find the Completion Progress block and click 'Overview of students'
6. For the test student, click the link (rectangle) corresponding to the label resource

Expected behaviour:

User is taken to the course page anchored at the label in question

Observed behaviour:

User receives error 'A required parameter (instanceid) was missing'

Stack trace:

• line 494 of /lib/setuplib.php: moodle_exception thrown
• line 568 of /lib/moodlelib.php: call to print_error()
• line 38 of /blocks/completion_progress/overview.php: call to required_param()

Additional notes:

If for whatever reason it isn't possible to link to the label resource within the course page, at the very least the user shouldn't be presented with a code-level error message.