AC solution gives WA on resubmitting!

I was going through ‘All Submissions’ of the problem with code: COOLING (COOLING Problem - CodeChef).

I found a submission by ‘blackpanther’ (CodeChef: Practical coding for everyone).

I couldn’t understand the logic behind the code, and so I submitted it to see how could it work!

I got WA with the same solution (CodeChef: Practical coding for everyone)

Am just a little confused, as to how is this possible?

The only reasonable explanation can be the updation of the test cases without rejudging the already submitted solutions.

The solution must have passed the previous test cases; however, fails for the updated ones…

The problem is easy, however. The editorial is also provided. You need to greedily assign the lightest pie to the rack having the least capacity which can hold the pie successfully.

Waiting for an appropriate answer! Someone look into the matter please!

Ik how to solve the problem, I was just confused over the judging process!