Not sure where to post this so I'll just put it here.
The game started to act up the other day when I went back to Forbidden Woods to open all remaining chests on my file. I were playing the Digital Version, installed directly onto the Wii U, so it can't be the dvd or exteral hdd acting up.
The screen began to flicker and shit. Blue and black boxes appeared on screen.
The speed and amount of this seemed to decrease as I went higher into the room, and increase as I went back down.
A moblin were walking in the floor (he was rotated 90 degrees so it was like he was lying on the floor), but he was killed by the other moblin before I uploaded a picture to miiverse.
No issues with the sound, and I didn't have a video cable connected as I were playing on the gamepad, so I couldn't see if it had any other effects on audio/video for the big screen.
It happened in the Boss Key Room on a ng+ file that had just finished earth temple. I recall doing a savewarp after initially getting the BK to skip the battle sequence in that room.
I also have a bunch of pictographs that I took while the graphics were still being messed up.
I'd guess that this was just some random glitch that occured, similar to the lighting glitch on GC (I don't know much about it at all, so I don't know), but the rotated goblin makes me doubt that.
The effect went away when I exited the room, but it remained through saving, screen swapping, pause menues and all that stuff. No freezes or oddities occured for the rest of the session. And I played for at least a few more hours.