I'm inclined to agree with this. I compared my new 11 Pro out of the box to floor models in 2 local Apple stores, and the demo models were definitely slightly cooler, but dimmer at max brightness (with TT and AB off). Obviously, their screens would be more "broken in" than mine. I've also been measuring color temp at pure white for the past 3 days, and the screen itself has gotten about 200 Kelvin cooler since I unboxed it 4 days ago. Was 6553K, now 6760K. Don't know how long that trend will last, but there's definitely some kind of reaction/aging/drying gong on.
That said, I calibrated my macbook pro monitor to nec 709 (which would contain a D65 whitepoint). It also now measures about 6600 K, but looks noticeably cooler with purer whites than my 11 Pro. I think Apple may be playing with RGB values in software somehow - handicapping blue, or augmenting red - but still keeping it on the 6500K curve.
In any case, it's completely inexcusable that we can't embed icc profiles, or at a minimum, independently adjust RGB channels and white balance, like we can on any TV set made in the last forty years.