Graphical glitches on Intel Graphics when Xorg started on Iris driver

There are graphical glitches in multiple applications when Xorg started on Iris driver, which is the default behavior now. The problem happens on Mesa 20.0.0 and on Mesa 19.3.3, i haven't tried other versions.

The problem doesn't happen if i run Xorg on i965 driver, like this:

MESA_LOADER_DRIVER_OVERRIDE=i965 startx

And then, even if i run other applications on Iris driver, the problem doesn't happen. So the glitches are present only if Xorg itself started on Iris driver.

Interesting that the glitches much less noticeable when i record my screen using ffmpeg, so i had to record my screen using external camera.

Here is the demonstration

My iGPU is Intel HD 630

I use Xorg's modesetting driver, i don't use xf86-video-intel.