Hi there,
Their is no details on the bug report for this behavior. Windows 11 known issues and notifications
https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-21h2
A driver update is the first thing you should do regardless of what device you’re using. Many Windows users reported that doing this fixed their issues with the brightness not adjusting. Go to Control Panel > System and Security > Power Options and check that your power options aren't affecting the brightness on your screen.
Update drivers manually in Windows https://support.microsoft.com/en-us/windows/update-drivers-manually-in-windows-ec62f46c-ff14-c91d-eead-d7126dc1f7b6
You can also try the SFC & DISM scan . Use the System File Checker tool to repair missing or corrupted system files https://support.microsoft.com/en-us/topic/use-the-system-file-checker-tool-to-repair-missing-or-corrupted-system-files-79aa86cb-ca52-166a-92a3-966e85d4094e
-----------------------------------------------------------------------------------------------------------------------------------
--If the reply is helpful, please Upvote and Accept it as an answer--