BUG #7760: records with duplicate primary keys

The following bug has been logged on the website:

Bug reference: 7760
Logged by: Alan Cummings
Email address: acummings(at)aperiogroup(dot)com
PostgreSQL version: 9.1.7
Operating system: Ubuntu Linux 10.04.1
Description:

We found 6 duplicated primary keys in a table. All fields were identical in
the duplicated records, including the primary key. (Total records ~ 22,000).
We recently updated from 9.1.2 to 9.1.7, so the issue may have been present
in 9.1.2.

We have fixed the issue in our table by backing up the table in pgAdmin to a
plain file, deleting the duplicated records in the text file, then restoring
the table.

I can send the original backup with the duplicated records if that would be
helpful -- it is about 11MB.