I've encountered an unusual problem on two D810 bodies now. Luckily, the shop I bought my first body from last week agreed to replace it, but when I used the replacement body tonight I had the same problem (please see the image below). Has anyone else had this happen? It certainly doesn't look to be normal to me, and I've never seen a noise issue like this. This image was opened in Photoshop and saved to jpeg with no other processing. I'd be grateful of your opinions on what it might be - or have I just been unlucky?