psql or pgbouncer bug?

Hi,

can anyone tell me how this could happen, please?

database=# begin; update table set col = 100;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.
UPDATE 153
database=# ROLLBACK ;
WARNING:  there is no transaction in progress
ROLLBACK

The update was commited to database. This was psql 8.4 connectig to 8.2
server through pgbouncer 1.3.

It's not reproducible for me :-(

Any ideas?

Thanks,

Kuba