Comment # 15 on bug 97119 from Johannes Hirte

(In reply to Michel Dänzer from comment #14)
> Which 'Tearing prevention ("vsync")' mode are you using in the kwin
> compositor settings? Maybe attach a screenshot of that settings page.

Was "Automatic" , but test with "Never" shows the same behavior. I've suspected
glamor to be related here, but a test on Sumo with AccelMethod glamor doesn't
reproduce the error.