A few weeks ago, Stephen Munn over at Aeropause reported that Nintendo was replacing Twilight Princess discs (Wii version) that had been affected by the "Cannon Room Glitch." Stephen unfortunately got caught in this trap and dutifully returned his disc to Nintendo for replacement. Well, the new disc came back and Stephen says that once again all is well in Hyrule.
Starting the new Zelda disc the first time brings a message, "Initiating System Update." On confirmation, it does a very quick update (apparently from the disc), and then brings you back to the Wii Menu... Upon opening the game, Shad is in the room. Speaking to him makes him leave.
The problem with this bug was that the character of Shad was nowhere to be found in the room to talk to after saving and shutting off the console in the Big Cannon Room. If you talked to Midna and tried to warp out of the room, she would tell you you couldn't because "That guy is watching us." Searching for Shad in the room came up with nothing despite what some forums would have you believe about him being "invisible", thus making it impossible to leave the room.
So, if you were a victim of this unfortunate incident and were unsure about sending your disc back, you can rest assured that the new replacement will fix the issue. There is no word yet on whether this will also fix the Eldin Bridge glitch that was also present on some versions.