HDR Randomly Fails with AMD GPU

Description: When using HDR on a Plasma 6 desktop, HDR activation is inconsistent after rebooting, switching TTYs, or toggling HDR on/off. This results in KDE Plasma outputting an HDR signal, but the screen does not switch to HDR, leading to a washed-out, grayish picture.

System Information:

GPUs Tested: AMD 6900XT and 7900XTX
Operating System: Arch Linux with kernel 6.10 (issue persists across multiple kernels)
Graphics Stack: Mesa 1:24.1.4-2
Adapter: Cable Matters 102101-BLK (as referenced in freedesktop issue #1417)
Monitor: LG OLED C2

Steps to Reproduce:

Enable HDR on a Plasma 6 desktop.
Reboot, switch TTYs, or toggle HDR.
Observe the HDR activation inconsistency.

Expected Result: HDR should consistently activate when enabled.

Actual Result: HDR activation is inconsistent:

HDR sometimes works correctly.
HDR sometimes results in a washed-out, grayish picture.

Additional Information:

Dual Monitor Setup: Sometimes both monitors work with HDR, sometimes only one, and sometimes none.
The issue might be related to using DisplayPort to HDMI 2.1 adapters due to lack of HDMI 2.1 support in AMD GPUs.

Thank you for addressing this issue. Please let me know if further information or testing is needed.