Lexar cards acting strange in Aperture

Several of my Lexar cards are behaving oddly. Might not be a Lexar issue, but in Aperture when I try to import images the CF card appears multiple times in the list of drives, but clicking on them doesn't show any images to import. They also won't eject unless I go to the finder and dismount the drives by hand. If I transfer the images to my hard drive they import without an issue. I'm using a Nikon D800. I don't appear to have problems with my D700.