I have on noticed this. Apple has really done a remarkable job on the new Retina Flash. Quite some people seem to think the screen just lights in white, but there's way more behind it. First of all it lights up the display brightness by 3 times the original maximum brightness. Second, just like the True Tone flash at the back, the Retina Flash tries to match the color of the ambient light, skin tones etc.
All to get those accurate colors. 🙂
Anyway, it just works. And that's all we want, right?