Well, it’s good to hear that it is a card failure.
However, I personally would rather physically mail the card to someone at Sound Devices (Nelson? Yes, you, Nelson. I’m looking at you) so they could check it out, send you a replacement, and keep track of who you are. Let’s say the card checks out perfectly well. Then maybe it might wind up being your deck (or some third explanation). But if you send it into your dealer and eventually it gets checked out by SD and nothing wrong is found, then how are they going to tell you that?