As the original reporter, I’m confirming that 5.20.0-0ubuntu2 from -proposed does contain the fix for this bug, i.e. the issue I reported above is no longer reproducible. I’m only hesitant about tagging this ’verification-done’ because PerformingSRUVerification is pretty adamant about having a solid test case and I’m not sure my sloppy initial report qualifies.

jani@saegusa:~$ LC_ALL=C apt-cache policy unity
unity:
Installed: 5.20.0-0ubuntu2
Candidate: 5.20.0-0ubuntu2
Version table:
*** 5.20.0-0ubuntu2 0
500 http://archive.ubuntu.com/ubuntu/ precise-proposed/main amd64 Packages
100 /var/lib/dpkg/status
5.18.0-0ubuntu2 0
500 http://archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
5.10.0-0ubuntu6 0
500 http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages