32gb Extreme CF card reads as 8gb on C300

Hi everyone. I have a 32gb Extreme 60mb/s CF card that I’ve been using in a 7D and thats been working fine for several months. The other week I rented a C300 and after initializing the card in the camera, all of a sudden it would only read as 8gb. After plugging it into a card reader I could see that an 8gb partition had been created on the card, and when I formatted the card in the 7D or on the computer it would go back to 32gb, only to revert to 8gb in the C300!

Luckily I had plenty of cards for the shoot - 5 other identical 32gb cards all worked fine, and only this one played up. Do I have a bust card? Has anyone else had this problem and is there something I can do to fix it??