Ha ha, I like how I was partially there in all of my guesses.
Instead, I identified the changes as a lift in the shadows, which perceptually (at least for me) did get a little livelier by means of color (hue and saturation).
As for the flattening of greens and blues in the shadows and overall decrease in blues, I was thinking in terms of the histogram. I meant that more pixels in the shadows had become green and blue, green in the darks and blue in the darkest darks (decrease in blues compared to greens).
As for my comment on limiting changes in the reds in the forest image, maybe it is just personal taste but I prefer the darkest darks to be less saturated. A less reddish purple might make it less distracting (warm) especially for an image that is dominated by shadows and has less blue in it, which explains why the bridge over water and under sky image was more effective.
Just my thoughts. I am bad with color, so take this with a grain of paprika.