Mac OS colosync may be broken.
This question/comment is regarding Mac OS colorsync mistmatch with PS/LR rendering.
Problem: Despite proper calibration and ICC profiles, rendering of shadows in quicklook/preview differs from PS/LR. My inclination is to trust PS/LR rendering, as the OS (I'm assuming Metal api) rendering of the same image (grey patch ramp from 1-40) crushes the blacks in the first row. Could have future implications for PS/LR if Metal rendering is further integrated.
Testing conditions: Mac OS 10.14.5/6
2018 Mac mini, 2015 Macbook Pro 13"
Latest versions of each app.
Monitor calibrated with i1Display Pro to sRGB target colorspace, gamma 2.2, 120 cd/m2, native contrast
Proper monitor profile selected in system preferences.
Same image (located at www.lagom.nl) loaded in PS and Preview.
Issue can be replicated on both machines reliably.
Comments: This issue has been driving me insane, though the effect is obviously more subtle in real-world examples of images (photography). From what I can find online, it appears to be a longstanding issue at the OS level by Apple. For whatever reason, applying different gamma/blackpoint is suspected. Most visible in near black tones as demonstrated above. I've been in contact with NEC's director of software development for a number of problems relating to this.
Additionally, GPU rendering in LR is also subtly different than off for the same image. Not as severe as the above example, but noticeable when knowing what to look for.
It's likely an OS issue, which is very disappointing. I'm hoping Adobe can work with Apple to get to the root of this problem.
Any insights would be greatly appreciated. If you can replicate the issue on your own machines, please do chime in. It'll help develop a case.