HERE is Sprint recognizing it as their problem and claiming to fix it sometime in the future with a software update.
And the reason i believe that article is to placate people and doesn't at all address the problem is, it's been established 100x's over that replacing the SD card solves the problem. This would mean the SD card is the issue right? So how can you fix an SD card with a software update? Thats weird.
I replaced my SD card back on black friday (picked up a class 10 8gb card for $25) and haven't had a single mount/dismount issue since then which is almost a month now.
HERE is a thread you can check out with others who had the problem and found relief by replacing the card.
Should you have to spend your money on a new card? no. Sprint should replace them BUT it's a class 2, 2gb card ... do yourself a favor and replace it anyway