Comment # 3 on bug 80827 from Michel Dänzer

(In reply to comment #1)
> After quick bisecting, it looks like commit "radeonsi: Use dma_copy when
> possible for si_blit." (5d5c20920e0e570742a497aa047e99a2fa3c04f2) is
> responsible for that.

See bug 80787.

> When reverted, the full screen corruptions disappear, but window menu 
> corruptions still persist.

The kwin menu corruption is most likely a glamor bug. You can work around it by
selecting 'Raster' for the rendering engine in the kwin advanced desktop effect
preferences.