Ubuntu Printing defaults to mirrored printing

[ts]

ubuntu 13.04, cups installed, printer driver:
HP Color LaserJet CP3505 Postscript (recommended) (color, 2-sided printing)
Defaults: job-sheets=none, none media=iso_a4_210x297mm sides=one-sided
in CUPS the mirror image is disabled.

yet: ever since one of the last system updates ubuntu printing defaults to mirrored printing (which is really annoying, of course). Using the gnome-control-center -> printers -> options it is impossible to switch off "Mirror Image", it immediately is switched on again automatically, upon each click.
Disabling it in the normal printing dialog is possible, and necessary, for each print job (which, again, is really annoying).

Checked dconf-editor and configuration editor for "printing" or "mirror" settings, but didn't find anything.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: gnome-control-center 1:3.6.3-0ubuntu24.1
ProcVersionSignature: Ubuntu 3.8.0-25.37-generic 3.8.13
Uname: Linux 3.8.0-25-generic x86_64
ApportVersion: 2.9.2-0ubuntu8.1
Architecture: amd64
Date: Thu Jun 20 14:34:54 2013
ExecutablePath: /usr/bin/gnome-control-center
InstallationDate: Installed on 2012-12-17 (184 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-control-center
UpgradeStatus: Upgraded to raring on 2013-05-07 (44 days ago)
usr_lib_gnome-control-center:
 activity-log-manager-control-center 0.9.4-0ubuntu6.1
 deja-dup 26.0-0ubuntu1
 gnome-control-center-signon 0.1.6bzr13.04.05-0ubuntu1.1
 gnome-control-center-unity 1.2daily13.04.09-0ubuntu1
 indicator-datetime 12.10.3daily13.03.26-0ubuntu1

[ts (toto-23)]

gksudo gnome-control-center shows the mirror image option to be turned off, turning it on and off again as root does not change anything. starting gnome-control-center in user mode still defaults to mirror image and flips back to "on" on any attempt to switch it off.