I also have a little problem, see attachment..That's pretty much how some of my photos looked like when trying to import into Aperture/Lightroom 4.
Didn't notice it on the LCD screen and it appeared when I zoomed in to a 100% in Adobe Bridge. After that it also appeared on the thumbnail in Bridge. I'm hoping this is just a PC / software issue and will be resolved with a new Camera Raw update?
Edit: No problems with the rest of the 500 shots I took. My CF card is only 4 GB and pretty old.
No issues with jpegs from the MkIII, and no issues with RAWs from a MkII already on the card.
Guess we await a few fixes, and both LR and Aperture, Bridge to handle MkIII files