It happens to me too, but it's completely normal, and it should be doing it on everyone's copy. It's simply the laser transitioning between the two layers of the disc. When more dual-layer game discs are released, they will do the same thing.
Even some DVDs have a warning on the back of the cover: "Layer transition may trigger a slight pause". But keep in mind that while DVD movies are streaming media, Wii games are burst media, which leads to longer load times, rather then small pauses in-game.
27/06/2008
Super Smash Bros. Brawl
"Populating Tag Error" upon visiting Page 2 of Robtot's Comics :/