Unity chameleon effect reverts to pre-update colour

I had an orange-ish wallpaper as my background picture under ubuntu 12.04, and the launcher adopted, as expected, an orange-ish tone that matched it. After a software update last week (I can't recall the exact date), I noticed that, if I changed wallpapers, the chameleon effect would work properly but that, after restarting the system, it would go back to the orange-ish tone that I had before the update. The only exception to this are the system notifications, that work as expected. If I change the wallpaper again, the chameleon effect works normally, until a new restart.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.12-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.2.0-26.41-generic 3.2.19
Uname: Linux 3.2.0-26-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
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
Date: Tue Jul 10 11:46:25 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
DkmsStatus:
 virtualbox, 4.1.12, 3.2.0-25-generic, x86_64: installed
 virtualbox, 4.1.12, 3.2.0-26-generic, x86_64: installed
GraphicsCard:
 Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Device [103c:30e1]
   Subsystem: Hewlett-Packard Company Device [103c:30e1]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MachineType: Hewlett-Packard HP EliteBook 2530p
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-26-generic root=UUID=03d218da-4cf7-445e-9ed7-5b9e14156d90 ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/14/2009
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 68PSU Ver. F.0E
dmi.board.name: 30E1
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 03.1B
dmi.chassis.asset.tag: CZC94908YD
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr68PSUVer.F.0E:bd09/14/2009:svnHewlett-Packard:pnHPEliteBook2530p:pvrF.0E:rvnHewlett-Packard:rn30E1:rvrKBCVersion03.1B:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP EliteBook 2530p
dmi.product.version: F.0E
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.7.8-0ubuntu1
version.ia32-libs: ia32-libs 20090808ubuntu36
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu3.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu3.1
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10.3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1.2
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