Double sequence increase on single insert with RULE on targeted table

Dear All,

A program produces the wrong output for any given input.
Here comes bug report:
1. Database dump is attached.
2. Input: "BEGIN; INSERT INTO test1(some_text) VALUES ('test1'); SELECT
lastval() as id; END;"
3. Output:
INSERT 0 1
id
----
3
(1 row)
4. Exspected Output:
id
----
2
(1 row)
5. Environment:
ANT_HOME=/usr/share/ant-core
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="00" [2]="16" [3]="2" [4]="release"
[5]="i686-pc-linux-gnu")
BASH_VERSION='3.00.16(2)-release'
CLASSPATH=.
COLORTERM=gnome-terminal
COLUMNS=124
CONFIG_PROTECT='/usr/lib/mozilla/defaults/pref /usr/lib/X11/xkb
/usr/kde/3.4/share/config /usr/kde/3.4/env /usr/kde/3.4/shutdown
/usr/share/config'
CONFIG_PROTECT_MASK='/etc/gconf /etc/terminfo /etc/splash'
CVS_RSH=ssh
DCCC_PATH=/usr/lib/distcc/bin
DESKTOP_SESSION=default
DESKTOP_STARTUP_ID=
DIRSTACK=()
DISPLAY=:0.0
DISTCC_LOG=
DISTCC_VERBOSE=0
DM_CONTROL=/var/run/xdmctl
EDITOR=/bin/nano
EUID=1000
FLTK_DOCDIR=/usr/share/doc/fltk-1.1.6/html
GCC_SPECS=
GDK_USE_XFT=1
GROUPS=()
GS_LIB=/home/sarunas/.fonts
GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/sarunas/.gtkrc-2.0:/home/sarunas/.kde3.4/share/config/gtkrc
GTK_RC_FILES=/etc/gtk/gtkrc:/home/sarunas/.gtkrc:/home/sarunas/.kde3.4/share/config/gtkrc
G_BROKEN_FILENAMES=1
HISTCONTROL=ignorespace
HISTFILE=/home/sarunas/.bash_history
HISTFILESIZE=500
HISTSIZE=500
HOME=/home/sarunas
HOSTNAME=sarunas
HOSTTYPE=i686
IFS=$' \t\n'
INFOPATH=/usr/share/info:/usr/share/binutils-data/i686-pc-linux-gnu/2.15.92.0.2/info:/usr/share/gcc-data/i686-pc-linux-gnu/3.4.4/info
JAVAC=/opt/sun-jdk-1.5.0.05/bin/javac
JAVA_HOME=/opt/sun-jdk-1.5.0.05
JDK_HOME=/opt/sun-jdk-1.5.0.05
KDEDIRS=/usr
KDE_FULL_SESSION=true
KDE_MULTIHEAD=false
KDE_NO_IPV6=1
LESS=-R
LESSOPEN='|lesspipe.sh %s'
LINES=45
LOGNAME=sarunas
MACHTYPE=i686-pc-linux-gnu
MAILCHECK=60
MANPATH=/usr/local/share/man:/usr/share/man:/usr/share/binutils-data/i686-pc-linux-gnu/2.15.92.0.2/man:/usr/share/gcc-data/i686-pc-linux-gnu/3.4.4/man::/opt/sun-jdk-1.5.0.05/man:/usr/qt/3/doc/man
MC_TMPDIR=/tmp/mc-sarunas
MOZILLA_FIVE_HOME=/usr/lib/mozilla
OLDPWD=/home/sarunas
OPENGL_PROFILE=xorg-x11
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PAGER=/usr/bin/less
PATH=/usr/local/bin:/usr/bin:/bin:/opt/bin:/usr/i686-pc-linux-gnu/gcc-bin/3.4.4:/opt/sun-jdk-1.5.0.05/bin:/opt/sun-jdk-1.5.0.05/jre/bin:/usr/qt/3/bin:/usr/kde/3.4/bin:/usr/games/bin
PERLIO=stdio
PIPESTATUS=([0]="0")
PPID=9438
PRELINK_PATH_MASK='/usr/lib/gstreamer-0.8:/opt:/lib/modules:/usr/lib/locale:/usr/lib/wine:/usr/lib/valgrind:/usr/bin/mencoder:*.la:*.png:*.py:*.pl:*.pm:*.sh:*.xml:*.xslt:*.a:*.js'
PROMPT_COMMAND='pwd>&8;kill -STOP $$'
PS1='\[\033[01;32m\]\u(at)\h \[\033[01;34m\]\w \$ \[\033[00m\]'
PS2='> '
PS4='+ '
PWD=/home/sarunas/Cargo2Net
PYTHONPATH=/usr/lib/portage/pym
QMAKESPEC=linux-g++
QTDIR=/usr/qt/3
SESSION_MANAGER=local/sarunas:/tmp/.ICE-unix/8550
SHELL=/bin/bash
SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
SHLVL=3
SSH_AGENT_PID=8504
SSH_ASKPASS=/usr/bin/gtk2-ssh-askpass
SSH_AUTH_SOCK=/tmp/ssh-SGMtSU8503/agent.8503
TERM=xterm
UID=1000
USER=sarunas
WINDOWID=29373840
XCURSOR_THEME=gentoo-silver
XDG_CONFIG_DIRS=/usr/kde/3.4/etc/xdg
XDG_DATA_DIRS=/usr/kde/3.4/share:/usr/share
XDM_MANAGED=/var/run/xdmctl/xdmctl-:0,maysd,mayfn,sched,rsvd,method=classic
XINITRC=/etc/X11/xinit/xinitrc
_=/etc/profile
safe_term=xterm
use_color=true
6. Postmaster startup options:
su - postgres -c '/usr/bin/pg_ctl start -D
'\''/var/lib/postgresql/data'\'' -s -l
'\''/var/lib/postgresql/data/postgresql.log'\'' -o '\'''\'''
7. PostgreSQL version:
PostgreSQL 8.1.0 on i686-pc-linux-gnu, compiled by GCC
i686-pc-linux-gnu-gcc (GCC) 3.4.4 (Gentoo 3.4.4-r1, ssp-3.4.4-1.0,
pie-8.7.8)
8. Platform information:
8.1. Kernel: 2.6.12-gentoo-r10
8.2. GlibC: GNU C Library stable release version 2.3.5, by Roland
McGrath et al.
Copyright (C) 2005 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 3.4.4 (Gentoo 3.4.4-r1, ssp-3.4.4-1.0,
pie-8.7.8).
Compiled on a Linux 2.6.11 system on 2005-10-17.
Available extensions:
GNU libio by Per Bothner
crypt add-on version 2.1 by Michael Glad and others
Native POSIX Threads Library by Ulrich Drepper et al
The C stubs add-on version 2.1.2.
GNU Libidn by Simon Josefsson
BIND-8.2.3-T5B
NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.
8.3. Processor: Intel(R) Pentium(R) 4 CPU 2.80GHz
8.4. Memmory: 1024 GB
8.5. Linux ver: Gentoo 2005.1

Sincerely,
Sarunas