I do minimal processing, and don't touch the color adjustments in general (I'm new at this, and prefer to confuse one issue at a time). But the first step in all of my Nebulosity processing is the "adjust color background" process, because there's plenty of sodium vapor lamps near my house, and their color pervades almost every image taken hereabouts.

So I'd wager that the orange and yellow colors in the images are disappearing as collateral damage from the removal of the local light pollution. One of these days when I pick up a real mount for my nascent astrophotography attempts, I'll get out of town to some darker skies away from all these orange-colored streetlights!

Is it ok (given your location) to wish you a happy Independence Day?