Comment 6 for bug 868684

there was also 2 gnome-desktop3 uploads:

https://launchpad.net/ubuntu/+source/gnome-desktop3/3.2.0-0ubuntu3

"gnome-desktop3 (3.2.0-0ubuntu3) oneiric; urgency=low

  * debian/patches/00git_disable_dpms_timeouts.patch:
    - Disable DPMS timeouts (LP: #863038)"

https://launchpad.net/ubuntu/+source/gnome-desktop3/3.2.0-0ubuntu2

"gnome-desktop3 (3.2.0-0ubuntu2) oneiric; urgency=low

  * debian/patches/02_refuse_to_break_GL_compositors.patch:
..."

the first one could perhaps create such issues. Do you get the issue every time?