Created attachment 192829 [details]
In the "Configure Columns" window, is the desired configuration of process information columns. In the main window behind it, is what actually results from hitting OK.

DESCRIPTION
The below Observed and Expected results should highlight the issue I'm experiencing. An image with description has also been attached to this bug report.

STEPS TO REPRODUCE
1. Install the plasma system monitor package
2. Open the plasma system monitor app
3. Modify column order while adding GPU usage and memory columns somewhere in the middle
4. -----> Observe that the column order is not respected, and column duplicates exist.

OBSERVED RESULT
Column ordering is not as configured in the "Configure Columns" subwindow, and even contains duplicates for unknown reasons.

For unknown reasons, clicking OK in the "Configure Columns" subwindow and then bringing it back up is also unable to restore the items in the previously configured order either. Possibly related.

EXPECTED RESULT
Ordering should ideally be as configured in the "Configure Columns" subwindow, and no duplicate columns should be displayed.

SOFTWARE/OS VERSIONS
Operating System: CachyOS Linux
KDE Plasma Version: 6.6.5
KDE Frameworks Version: 6.26.0
Qt Version: 6.11.1

ADDITIONAL INFORMATION
I apologize if this is a duplicate issue.

I also apologize if this has already been fixed. If so, I would ask the CachyOS package provider to update their version of KDE Plasma to a version where this is fixed.