bear in mid edmund that the test shot was made in the most brutal spanish summer sunlight at 1000m in the toledan mountains, the heat was stifling... that intense direct sunlight tends to flatten everything & turn greens to yellow... i'm not saying your observation is wrong but it'd be worth further tests in more natural light.
If you look at that horrible image I posted, with the inverted channels, you can see how well my junkworthy 1Ds3 discriminates the *color shades* inside the leaves. I have no particular love for this camera, but you are doubtless aware of its reputation, uses and limitations: In its day it was Canon's studio and MF replacement product, a slow camera whose images degrade around ISO 400, but intended to convey nuance.
Here is a similarly inspired treatment of Quentin's image above, and you can see there is simply not that much color information in that image. My take on this is that Sony decided to capture and encode as much luminance information as they could in the available 14 bits (?) of DR, with the intent of allowing people to shoot for movies in available light, and they set the design priority on capturing and encoding luminance information rather than color differentiation. A different set of priorities would have meant 2 stops less DR and more precise color, which is basically the tradeoff on those old CCD backs and early studio oriented CMOS cameras. Contrarywise to the way everyone else here expects the laws of physics to be waived, I still believe in conservation laws in physics, and the in the no free lunch theorem.
In the full afternoon shadow in Paris, my shot was soft as with difficulty I eked out 1/80@F8@ISO400 on my ancient 1DsIII, precisely because the color filters on this camera are very orthogonal so it is not very sensitive, and to shoot it higher means destroying the color.
Do some more testing, by all means, but I think I've now seen enough images here and elsewhere to reach a conclusion; however every camera has advantages and disadvantages, and this one can certainly see deep into both shadow and sky, in a unique way. If it is at the price of some evanescent shades of yellow-green and green and blue green which most men would not percieve, who cares? In exchange, one will get well defined and textured images of the clouds above a landscape. The A7IIR is certainly the camera of the year. And if I may be allowed to say so, I think you have a very nice sample of an extraordinary 50mm lens that is almost symbiotic with that body.
I'm sure everybody here will tell you that I'm an idiot who understands nothing about digital cameras and even less about color. You can come back in a few months and tell us what you have learnt from experience
Edmund