I have created one local adjustment via gradient mask or brush tool. In that that local adjustment I have made a color selection, adjusted hue, saturation etc. Now, in an attempt to fine tune the image, if I go and create a new local adjustment, which is partially over the 1st local adjustment. If I just do an exposure adjustment I am fine, however if I try to make a color selection in the new layer I get a dark area outlining the entire selection which ruins the selection.
You probably encountered a limitation in the design of the color editor. Conceptually, the color editor creates an ICC profile for each layer that contain color edits, which is relative to the camera profile with edits from the background layer.
This scheme has the advantage that colors can be edited very accurately - this is something we care deeply
about in the team and really does take precedence over most other issues. It does have a downside: if a layer with color edits have a 100% opacity in a given area, it will replace color edits in local layer below it.
There is a workaround in the case where the upper layer is a subset of the layer below: start the layer with the same color edits as the layer below. It sounds like this should be enough for your case. There is, unfortunately, not currently a way to copy local settings from one layer to another, so you need to do it by hand. Sorry.
Esben H-R Myosotis