[wulf]

If you could freeze the input from your naked eye, it is possible you might see something similar. As you look at a flower, your eye is scanning back and forth and your brain is interpreting the stream of information so you think you see a clean edge but the camera condenses information from a short period of time into a single image and an interaction is revealed between the different colours.

I don't think it mars the result in this shot. If you look the work of many painters, particularly the Impressionist school, you will see that their images are made up of many colours that, viewed in isolation, look completely wrong. However, stepping back to view the whole image they add richness.

I think the slight "discolouration" you are worried about serves to do the same thing and should not be a cause for concern. Is the "border" colour consistent all the way round or does it vary according to the background?

Wulf