Created attachment 115709 [details] broken fonts SUMMARY Broken fonts during scrolling happen only in System settings -> Desktop Behavior -> Desktop Effects. Everywhere else scrolling ok.Example screen-shot in attachment. STEPS TO REPRODUCE 1. open System settings -> Desktop Behavior -> Desktop Effects 2. try to scroll with with mouse wheel up and down OBSERVED RESULT Ugly broken fonts. Which in some positions of mouse wheel become nice looking. EXPECTED RESULT Nice and clean fonts. SOFTWARE VERSIONS (available in About System) KDE Plasma Version: 3.8.6 KDE Frameworks Version: 5.28.0 Qt Version: 5.7.1 ADDITIONAL INFORMATION As i seen in Internet it is very very old bug. Which not fixed during ages.
Fixed in a later version of Plasma, please upgrade. 5.14 was just released. If you prefer to stay with LTS versions, there's 5.12.