I'm having a very similar problem on my BARTS XT. 

It seems to only show up in apps that use OpenGL and only after a
suspend/resume cycle. I'm not using a desktop compositor, so i never see it
affect the whole screen like Rafał's screenshots.

Colors appear to invert or brighten randomly then go back to normal a couple
seconds later. Similar to the attached jpegs.

Linux Brimstone 3.12.3-1-ARCH #1 SMP PREEMPT Wed Dec 4 21:45:42 CET 2013 x86_64
GNU/Linux

OpenGL version string: 3.0 Mesa 10.1.0-devel (git-92ceb32)
OpenGL shading language version string: 1.30

local/ati-dri-git 60031.92ceb32-1 (mesagit)