ipf filter: froblem with "keep state" or "flags S" parameter

[Eugenijus Urbonas]

Hello!
Some time ago I already had business with ipf and everything was ok (I 
used manual to create rules), server worked perfetcly.
Now I'am trying to setup the same server, but with newer version of 
FreeBSD (8.1-RELEASE), the same manuals, the same settings, everything 
works except firewall, and there is something strange:
for example, I have rules in my /etc/ipf.rules:

Code:

pass out quick on fxp0 all
pass in log quick on fxp0 proto tcp from any to any port = 80
block in log first quick on fxp0 all

in this case ipmon shows:
Code:

... fxp0 *@0:1 p *xx.xx.xx.xx -> xx.xx.xx.xx,80 PR tcp len ...

that is OK

now I change second rule to:
Code:

pass in log quick on fxp0 proto tcp from any to any port = 80 flags S keep state

# because I want to use statefull firewall ofcourse

in this case ipmon shows:
Code:

... fxp0 *@0:2 b* xx.xx.xx.xx -> xx.xx.xx.xx,80 PR tcp len ...

and that is NOT OK

I don't understand why, but now my connection does not match my rule... 
why? can someone explain in to me?

May it be that there is some kind of bug and i have to patch my system?