Created attachment 151094 [details]
Image showing the issue.

SUMMARY
When enabling "Blur background" in profile appearance, you get weird coloring issues at the top corners of the window. I believe this is due to the blur mask extending too far near the rounded corners of the window when using the default Breeze window decorations (see this YouTube video for some discussion of a similar issue affecting all Plasma windows: https://youtu.be/FT-xaqL7HzU).


STEPS TO REPRODUCE
1. Launch Konsole, open the settings menu and select "Edit Current Profile..."
2. Go to "Appearance" and then click the "Edit" button the right hand side.
3. Select the "Blur background" option, apply and close the dialog. Drag the window around the screen placing the top corners over different color areas. Pretty noticeable the gray color at the top of this website.

OBSERVED RESULT
The top corners show odd colors (probably from a contrast boost) in the area which should be completely transparent for the rounded corners (see the attached image for an example).

EXPECTED RESULT
Corners should appear the same as every other application window, which does not have this issue.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Manjaro 21.3.6/ KDE Plasma 5.24.6
(available in About System)
KDE Plasma Version: 5.24.6
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5

ADDITIONAL INFORMATION