Created attachment 182802 [details]
Journal/stack trace from hdrcalibrator crash

SUMMARY
HDR calibration settings crash at startup after upgrading to the official plasma 6.4 release from the beta versions where it had been working. 

STEPS TO REPRODUCE
1. Launch "Calibrate HDR Brightness" (right-click on desktop > Display Configuration, or Settings menu > Diisplay & Monitor > Display Configuration followed by clicking on "Calibrate HDR Brightness", or running hdrcalibrator from a command line). 

OBSERVED RESULT
Screen may show briefly before crashing (what I see most often), or it may immediately freeze and require termination. In both cases, the effect is near instantaneous before any changes can be made, such as moving the button on the slider.

EXPECTED RESULT
The program should launch without crashing or freezing.

SOFTWARE/OS VERSIONS
Linux Kernels: 6.12, 6.15, and 6.16rc4 verified (LTS, current, and release candidate checked)
KDE Plasma Version: 6.4.1
KDE Frameworks Version: 6.15.0
Qt Version: 6.10.0
Mesa version: 25.1.4

ADDITIONAL INFORMATION
Running hdrcalibrator from the command line provides the following error:
"Job 1, 'hdrcalibrator HDMI-A-1' terminated by signal SIGSEGV (Address boundary error)"

I  saw two other bugs regarding this tool reporting a breeze icon theme dependence, but they seem unrelated. This is a crash rather than the issues with the icon appearing or absence,  Just in case, I also tested using breeze and other icon themes, but with no effect on the crash I am seeing.

I have also attached the stack trace from the journal when crashing. Please let me know what else I can do to aid in finding the root cause and fixing. Thanks in advance for your help.