Alright, I might have a clear answer. Bear with me here. Did this a few days ago.
I spent multiple hours getting this assignment. And then I played through this 15 times, quitting without saving.
12 - Saw this bug! Went as far as I could. Game crashes.
My brother works his life away in his room, coding and that good stuff. Gave the game to him.
He told me tonight about it. This "Dojo Registration" thing does in fact exist. Just within the coding of the game. It is extremely glitchy. If you somehow enter it, I recommend shutting down the system. Buggy!
Some things aren't actually implemented for a reason, I guess. Quite a few Nintendo games have locations, items, etc that aren't implemented.
This area does exist, but it isn't meant to and is a glitch.