So far, I haven't seen any official response from Apple. I went to the "Genius Bar" and they claimed ignorance. Then I talked to Calumet Camera. They know all about it. Guys like us are out of business if our business is based on "live proofing".
I use Capture One. Its the same story. Mountain Lion worked fine until the latest update. Now Apple / Canon are hiding their heads pretending that the issue isn't there. ********!!!
I use the Canon 5D mark II. Temporarily, I am using the Eye-Fi Pro SD card to transmit low jpegs to my Pwr Book. I have to use an adapter in my camera because it uses CF cards, not SD. It kind of works, but Eye-Fi's Tech Support says that the adapters cause issues. I've already had one.
During a shoot the card read, "Card Full". I transfered all the images, then erased all the images from the card. The camera still said, "Card Full"! The only way to get it working again is to plug it into the computer, lauch the disk utility, open the "erase" tab, and clear the card. Its working agian, but Eye-Fi says not to expect it to continue.
Come on Apple! Tethered shooting worked fine in the preliminary version of Mountain Lion. Fix it!!!