One of our instructors has a course where the following situation occurred:
1: Participant list is in the default arrangement (20 per page, sorted by Last Access).
2: exactly 20k+1 (21, 41, 61, etc) participants in the class.
3: two or more students (e.g. Yves and Zelda) have never logged in.
- Look at the first page (1-20) and see Yves at the bottom.
- Click the link for either Next or 2 (same thing).
- The sort order flips, and see Yves at the top of page 2. Zelda has fallen into a crack in the system and is never seen. Link, please rescue Zelda!
- Flip back and forth between the two pages enough times, and sometimes you will see one student or the other.
An instructor might not see one of the students in their roster for an extended period of time. Certainly, workarounds exist (e.g. change the sort order, or switch to Show All), but the bug occurs in the default sorting and is therefore more likely to be a problem.
Solution: students should always be sorted in the same order (e.g. add a secondary sort criterion to deal with Never logins).