but how??? how do you come off of a champions win, make ZERO changes and just bomb out of offseason events... I get it's offseason but damn you guys legit played in the exact same meta 3 months ago
This is not the same logic, because questions on tests are constantly fluctuating. This is from a champions winning team are ingrained in your brain from the entire year of prepping. You can take a break but you don't forget how to play the game, especially since they came back to practice in October.
A diagnostic test is a test (with the same topics from the previous year) taken to see where you are at the moment. I think it's pretty similar. Maybe the other teams came back to practice in October but EDG did not have their full roster together until a week before the Radiant Asia Invitational (as mentioned by Kangkang). Kangkang also mentioned that they will produce bad results due to a lack of practice.
By your logic, a champion-winning team should never lose again because they have the "champion level prep & gameplay" ingrained in their brains.