The first image you are seeing is the camera-generated JPEG. That can have major differences from the decode of the original for two reasons:
1) the camera JPEG has whatever settings you put in the camera, such as Picture Styles, Dynamic Range, and Sharpening, but the RAW does not.
2) The RAW decode is not designed to look like the JPEG anyway – Apple strives for a consistent look across camera models, not matching each camera maker’s JPEG (which is a moving target and also the algorithms in the camera are not documented anyway).
The easiest way to see this is to set your camera into Monochrome mode and take an image.
You have two choices: you can have that shift occur when you enter Edit, or when you are still in 1-up, before Edit. There is a preference in the app called Quick Preview. When you set that, the app will defer the decode until Edit.