workspace switching – effect 'move window' flickers twice

Precise 32-Bit 3D up-to-date

When switching workspaces by using CTRL+ALT+arrow up from a lower workspace to an upper workspace the compiz effect that lets the programs fly down from top is executed sometimes twice.
On faster systems the screen flickers, on low end systems the user can see the windows move down twice.

See attached video: 'bug_compiz_flickers_workspace_switching.ogv'
(the big horizontal bars are related to gtk_RecordMyDesktop)

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.10.0-0ubuntu3
ProcVersionSignature: Ubuntu 3.2.0-20.33-generic-pae 3.2.12
Uname: Linux 3.2.0-20-generic-pae i686
.tmp.unity.support.test.0:

ApportVersion: 2.0.1-0ubuntu3
Architecture: i386
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CompositorRunning: compiz
CurrentDmesg:
 [ 23.836520] radeon 0000:01:00.0: alignments 1728 64 8 256
 [ 23.836524] [drm:radeon_cs_ioctl] *ERROR* Invalid command stream !
 [ 25.499872] init: plymouth-stop pre-start process (1163) terminated with status 1
 [ 29.768041] eth0: no IPv6 routers present
Date: Sun Apr 15 18:35:59 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
GraphicsCard:
 Advanced Micro Devices [AMD] nee ATI RV620 LE AGP [Radeon HD 3450] [1002:95c6] (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Device [1043:0028]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120227)
MachineType: VIA Technologies, Inc. P4X266-8233
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-20-generic-pae root=UUID=c8bf2162-6667-4798-8852-fc36cfeec586 ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/03/2001
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: 6.00 PG
dmi.board.name: P4X266-8233
dmi.chassis.type: 3
dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvr6.00PG:bd10/03/2001:svnVIATechnologies,Inc.:pnP4X266-8233:pvr:rvn:rnP4X266-8233:rvr:cvn:ct3:cvr:
dmi.product.name: P4X266-8233
dmi.sys.vendor: VIA Technologies, Inc.
version.compiz: compiz 1:0.9.7.6-0ubuntu1
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20111219.aacbd629-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2