DP2M macro moire?
You are shooting at -1.6 bias which puts you at 326 ISO. You are also getting some underexposure due to the bright sky. When you push the image with SPP the color banding is shown in the darker parts of the image. If you must use a negative bias be sure to use 100 ISO.
|Thunderheads With Egret by Buzz Lightyear|
|Double Rainbow; Abiquiu, NM, USA. by abiquiuense|
from After the Rain