No, I am not relying on different physics. But as I was implying and as you pointed out refraction when it comes to optics like elements can contribute to what you see. I know what the definition of CA is. What is the exact physics behind it? Is it not different wave lens reaching different portions of the lens, especially when the light is bend aggressively and not compensated accordingly? So I when I say that generally I wouldn’t put optical elements in the frame to judge CA such. As gems or glass or ice etc it is to eliminate a potential contribution to the result. After all if one holds a gem up to the life and twist it this way and that one can general manipulate it to see a verity of colors. That includes purple and green those it not? So gems do bend light and can be a cause of a higher than “usual” incident light into the lens, which one can’t attribute.
Yes, the physics is the same, but you're relying on physics at a vastly different scale. Refraction from lens elements results in separation of wavelengths on a µm-scale, refraction from an object in the field of view is not the same. From the standpoint of a subject LoCA results from reflection, not refraction. Consider: why is it that LoCA – no matter the source – shows up as purple and green? To (re)quote you (with typos corrected): "
After all if one holds a gem up to the life light and twists it this way and that one can [in] general manipulate it to see a verity variety of colors." That's obviously true, so why does the LoCA observed in jewelry pictures* not show a variety of colors, but rather only two? Because the LoCA is not resulting from refraction through the subject, but only through the lens elements.
*There's a caveat there, that the gems need to be clear. If the gem is colored, the light from it will not be white and the way in which that light is refracted by the lens elements will be affected. But that's not the case here, as the jewelry under discussion contains only clear gems.
Of course if this was shown for those interested in taking pictures of jewelery specifically I get it can be useful. But as a blunt example of CA control... eh, grain of salt.
So if one is interested in sharpness, ISO 12233 charts are only useful for those interested in taking pictures of flat, printed subjects?
Regardless, look at the jewelry LoCA image, and notice that there are purple/green-fringed gems and that the setting is also purple/green-fringed, and that the intensity of the fringing is equivalent between the two. So let me ask you again, as an applied physicist – does solid metal refract light? If it does, then it's possible you're correct. But of course, we both know it doesn't.
As I stated previously, the 'extreme case' of LoCA is a specular highlight, and it really doesn't matter if that highlight is from a gem, polished metal, or another highly reflective surface.
Here's an example from a review of the RF 50/1.2. There is LoCA on the ring, no gems required.
Having said that, I do agree that the LoCA on the RF 50/1.2 is very well controlled.