Cannot install/purchase apps from app store with 'Brightness Upscaling' turned on; macOS 27.0

[RamKoPrasanna]

Look at update below: On macOS 27.0, m5 macbook pro, with Brightness Upscaling enabled: App Store pop-up for confirming install (the touchID animation, icon, and input) does not show and will not let you proceed with download until toggling off Brightness Upscaling.
Work around: un-toggle Brightness Upscaling > download app > re-toggle Brightness Upscaling.

UPDATE: Although this workaround worked for installiing apps on app store, I noticed when I played HDR video there was another 'bug' where the video would freeze on the current frame. I tried un-toggling Brightness Upscaling but that wasn't the issue.
When I looked through my config settings, I found that the cause for both App Store pop-up misbehaving and HDR Video issue was due to the "Saturation" setting (under image adjustments) being set to 1.07. Retuning that value to default (1.00), fixed both issues.

[waydabber]

Hi there,

I recommend trying "Direct brightness control and XDR upscaling" (if you regularly play HDR content, you may also want to turn on "Force EDR mode" under additional settings).

Alternatively, enable "Color Table Control" for software brightness upscaling (this is the default setting - but note that color table control seems to be broken on some M5 Pro and M5 Max systems, this is a known issue acknowledged by Apple).

With both of these turned off, brightness upscaling uses a compositor filter overlay technique as fallback (just like saturation control). Any kind of overlays will interfere with App Store and general TouchID UI - this is a security feature in macOS and works this way by design.

The HDR video issue is probably a separate one - image should not freeze with compositor filter overlays (like saturation), or at least I could not reproduce this issue on my M3 Max (tried Safari, IINA, did not try HDCP protected content with this - I am not sure about which player did you try).

[RamKoPrasanna]

Hi, I wasn't expecting a reply!

I actually had both XDR upscaling and the Force EDR Mode enabled (plus the saturation slightly turned up) when I encountered this. I am not exactly sure why I was able to toggle off direct brightness upscaling (while having saturation turned up), and that resulted in being able to download apps. It seems like if you have both the XDR upscaling AND the saturation 'tuned', then there is the app store security interference, but if I turn only 1 of them off, then the TouchID shows up normally. Also, it seemed to only interfere when inside the App Store (at least in my experience). Login worked for me, Settings TouchID prompts worked as well.

Btw, this really was not a real problem for me, I originally created the issue ticket just so the info was available to others.

The HDR video playback was something I noticed a while ago when I was trying to view one of the Apple screensavers in quickTime Player (the official wallpapers from Apple), I figured it was just Apple and how they had formatted their background/wallpaper videos, but then today I came across this video: https://youtu.be/_0bwJM-uTd8?si=u1pE5kbDrb7wi9QQ
and saw it happen here, and if I toggle off/on "Suspend image Adjustments" with saturation tuned up/down, I am able to consistently reproduce that 'bug'. I believe this is a HDCP thing, but it's a little odd. What I see is: 85% of 1 frame frozen, then 'under' that frozen frame I see the video playing. If I move my mouse off the video, the whole frame freezes, if I hover my mouse ove the video, then I see that weird frozen frame with the video playing under it. (this is quite literally the best way I can describe it). I observed this behavior with Apple's screensavers in quickTime Player and then that HDR youtube video in Chrome.
In safari, interestingly the same behavior is not present. Instead I see the framerate definitely takes a hit though. I'd say fps of the video is roughly 50% of original fps without having saturation enabled.

If you have any questions, i'd be more than happy to provide more details or experiment more!