Thanks for the comment Scott. I'm not sure what caused the halo but I may go back and look at the full size to see if I can remove it, at least on the ridge line.
I save my processed files as Jpeg so I went back to look at this one and there was no halo on the ridge line or people. I may have added some extra sharpening or who knows. Anyway I did a crop to produce a variation of the original showing the mountains and people better.