I strongly suggest avoiding use of this product until a fix is found and released.
I've spoken to BM support on the phone several times, and we're going to send one of our units to them to to look at in their lab. However, last time I spoke to them they "had received no other reports" of this issue. At the time I spoke them, there were several comments on the two form threads about this, and sent them the links. So if you're having trouble please call their support line: (408) 954-0500. Maybe if we all keep pressing this issue in numbers they'll admit/find/fix the issue and work towards regaining trust.
After experiencing this problem across our of units since August, we're finally removing and replacing our 9 units on Monday with solid but inferior products. This is going to be very costly for us, and embarrassing, increasing volume of lost recordings has become too much to handle.
We have tried several approved cards, different frame rates, different codecs. Once we had a file that would play in VLC, and was a corrupted file, but that was an anomaly.
This is a phenomenal product when it works! (Just missing H264 recording option for our use). But, we have lost all faith in it at this point. And, lots of credibility with our students and faculty...
other thread:
https://forum.blackmagicdesign.com/viewtopic.php?f=4&t=64802