It's less a matter of someone failing all the early tests but pulling a Hail Mary in the final, and more a matter of someone failing an early test because it to

It's less a matter of someone failing all the early tests but pulling a Hail Mary in the final, and more a matter of someone failing an early test because it took them an extra week to grasp the material; i.e., if the test had been offered a week later, they would have passed. So they still learned everything, just not on the artificial schedule imposed by one-off tests.