Created attachment 186821 [details]
Plasma 6.5.2's impact on theme appearance

SUMMARY
In Plasma 6.5.2, the intensity parameter does not appear to be honored and causes themes using it to look gray and ugly. No change was observed by tweaking the value. A screenshot comparing one of the working versions and Plasma 6.5 is attached.

STEPS TO REPRODUCE
1. Install and Apply a Plasma Style that leverages intensity (I used Sumac Day Molten Glass)
2. Ensure that your panel opacity is set to Translucent
3. Apply a white color scheme/switch to a solid white wallpaper/open a white window
4. Open a dialog over the white window, such as Kickoff

OBSERVED RESULT
Dialog is very gray and does not appear bright.

EXPECTED RESULT
Dialog appears close to white and maintains the appearance of a light theme.

SOFTWARE/OS VERSIONS
Operating System: CachyOS Linux 
KDE Plasma Version: 6.5.2
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0
Kernel Version: 6.17.7-3-cachyos (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
API changes are breaking. If this is related to the new Contrast Effect, should there not be versioning when doing these? If settings need to be changed for Plasma 6.5, then that means that the theme on the store may be broken for everyone with an older version for months if not longer.