Youtuber Octavio Galicia discovered a new problem Super Smash Bros. Ultimate which turns the characters into dark silhouettes during the game.
The Youtube video includes a tutorial to recreate the glitch, where the first player must have a Pro controller and the second one uses one of the GameCube PowerA cable commands or possibly any third-party Nintendo Switch that does not have a gyroscope.
After setting up the first player with the Pro Controller, start a sudden death game and choose the characters, the second player will have to choose the script. Once the game starts, both players will have to go through the control commands from the control settings in the startup menu, so now the Pro controller is set for the second player.
When returning to the title, the third-party player will have to choose the fighter. The next thing is to go to the pause menu and press the joystick to the right, which will cause the screen to become blue or black; when pressed again, the fault will appear.
You can see the full tutorial and a glitch sample below: