Shmoop explains what happened at TESU, says it's temporary...

[dfrecore]

I think it could possibly 1 student who passed so many tests that it wasn't humanly possible for 1 person to do that many credits in that amount of time. If you could show that it takes minimum of 1 hour to open a course and take all of the quizzes/tests for it, and that someone did this for say 30 courses in 1 day, then they couldn't possibly have finished that many courses in a single day - it's not logistically possible, even if they knew the material, and didn't take a break to eat, pee, or sleep. It would have had to take at least 1 other person to get through that number of courses, meaning that the person cheated.

It could be multiple people who did something like this, I wouldn't be surprised if it was that too.

But there has to be a bare minimum amount of time needed to pass a course, so there's a maximum number of credits you can get in a 24-hour period.