BUG #4070: Join more then ~15 tables let postgreSQL produces wrong data

The following bug has been logged online:

Bug reference:      4070
Logged by:          Marcello Ceschia
Email address:      Marcello.Ceschia@medizin.uni-leipzig.de
PostgreSQL version: 8.2.5 and 8.3.0
Operating system:   Windows XP
Description:        Join more then ~15 tables let postgreSQL produces wrong
data
Details:

We have an situation where we must join ~30 tables to get a general table.
Don't  ask why we do this this way.

After an unknown number of columns the joind values are not correct. We get
only the value from column 1.
If I separete the query and generate an temporary table with the first 20
tables and join them later with the rest one, all works fine.
All values in the result table are correct.

If you need more information, contact me I can send some example data.