You’re not using a Pi5 either, right?
I’ve downloaded the DNG from this post and the banding I see is negligible, even though the borders are black below 265.
But the image wasn’t taken with a Pi5, which is the only Pi I have.
@PM490 Since you managed to reproduce “my” banding in your reply. Are you also running a Pi5? 
Edit: When I roughly hold my hand between lens and gate and capture a photo, upping the exposure reveals rather intense banding.
If I’m closing the lid entirely, it’s this:
Is anyone able to reproduce this?
I’m starting to think I might have a bad camera cable connection. I replaced the cable for a longer one but picked a cheap one, admittedly… Also, there are two camera connectors on the board (I chose 0). But I’m hesitant to poke around without a hint, because it means dismantling Mr. Frankenscan up there and the original cable is just a tad too short 
.