https://bugs.freedesktop.org/show_bug.cgi?id=104598
--- Comment #6 from Christoph Haag haagch@frickel.club --- Yes, it's still happening. It's just running vkmark in default mode. It looks like this: https://youtu.be/MngLl6BgOfg
I'm not sure if previously it happened continuously but now it's only a couple of flips that fail (there's noticeable stutter visible when it happens).
Not sure how to make sure it doesn't use EGL but I ran it with KWIN_OPENGL_INTERFACE=glx kwin_x11 --replace, I hope that's enough.
Currently on kwin 5.12.5, xserver 1.19.99.905 g4191b59bd and latest xf86-video-amdgpu git so it has not been resolved there yet.
It happens with kwin's OpenGL 2 and OpenGL 3 backends and all vsync methods, including None. It does not happen with XRender.