BUG #10726: database gets to an older backup out of nowhere!!!

The following bug has been logged on the website:

Bug reference: 10726
Logged by: Walid
Email address: wildfox81(at)hotmail(dot)com
PostgreSQL version: 9.1.12
Operating system: Win 7
Description:

Dear All, I have a PostgreSQL 9.1 server working with a java 6 application
on windows 7. Sometimes I found that the db travels in time and many records
are missing. It's like the DB had been restored to an older backup. Because
some of these fields are according to its cascading structure is
un-delete-able. Even the auto IDs goes back as if some one truncated the
table and restore just that amount of data.

Even I turned off the auto vacuum, I do vacuum the db on regular bases. The
problem used to appear more often when I used the auto vacuum.
Please also note that:

- Once the data came back to the DB after around 20 hours, interesting, ha!
- Once the PostgreSQL log recorded a restore commands outs of no where. I
saw in the log when the DB was dropped, recreated, then data started to be
imported.

Any ideas, suggestions, similar accidents!!!