Dropped Frames on Certain SD Cards?

I have a Black Magic Micro Cinema Camera that I've been using the past couple of months. I love the camera, but it seems that when I use certain sized SD Cards, the camera seems to drop frames pretty often. I use both a 256GB and 128GB Sandisk Extreme Pro 95 MB/s SD Card. When I use the 128 GB card, no dropped frames, and it works like a charm, even when recording shots that are 20+ minutes on RAW 3:1. Yet when I use the 256 GB, it begins to drop frames after about 10 - 15 minutes of shooting. Anyone know what the issue is and how it can be resolved? Thanks!

Do not use the 256GB cards, theymseem to be problematic. Also, make,suremyiur 256GB cards are not counterfeit, and have up-to-date firmware (new cards vs older ines) on the SD cards, to checkmthis, you will need to contact SanDisk.

I have the best luck with the 128 GB San Disk cards, and that is what I use.
Cheers