Custom preset on Macbook Pro M1 XDR display have incorrect gamma

Hi,

I have a issue with the Liquid Retina XDR display on my Macbook Pro M1. When I create a custom preset with SDR Transfer Function set at pure 2.4 gamma the display is stuck at using pure 2.2 gamma. Just to make sure I tried setting the gamma at 1.0 and 3.0 and it still looked exactly the same as when using 2.2 gamma preset. When I use the SDR Transfer Function set at BT.1886 Annex 1 the gamma is correct.

I have calibrated the monitor (fine-tune with Calman) and apart from the gamma problem it's looking great with really low delta E on all presets (standard and custom).

I also tried with my wife's Macbook Pro M1 14" running the latest version of macOS Tahoe and it had the exact same problem.

What am I doing wrong or is the gamma function broken?

Setup

Macbook Pro M1 Pro (16" 2021)

Sequoia 15.7.1

Best,

Kristoffer