ftp-proxy problem

[Roman Gorohov.]

Hello, all.
We got a heavy load server with pf mostly doing nat and redirection.
[root at fw]#uname -r
6.1-RELEASE
[root at fw]#pfctl -sr | wc -l
     546
[root at fw]#pfctl -ss | wc -l
    9452
Traffic is about 8 Mb/s.
/etc/inetd.conf: ftp-proxy       stream  tcp     nowait  root    /usr/libexec/ftp-proxy  ftp-proxy -u proxy -m 55000 -M 57000 -t 180
/etc/pf.conf: rdr on $int_if proto tcp from any to any port 21 -> 127.0.0.1 port 8021 
Traffic is about 8 megabit/s.
All working ok until we turn on ftp-proxy. 
After that(and some time) server suddenly hang. 
Just hang, no kernel trap and clear console, didn't responding for any
key(I don't know how might that be, never expect it from BSD).
Meanwhile I can see one event relating to that - ftp-proxy.
And its not hardware issue, we got two identical server(hp dl 380, afair) working in carp, and both hanging. 
Last messages:
Dec  7 15:14:42 fw inetd[640]: ftp-proxy from 10.10.1.70 exceeded counts/min (limit 60/min)
Dec  7 15:14:44 fw inetd[640]: ftp-proxy from 10.10.1.70 exceeded counts/min (limit 60/min)
Dec  7 15:14:45 fw ftp-proxy[64195]: xfer_data (server to client): failed (Connection reset by peer) with flags 00
Dec  7 15:14:55 fw ftp-proxy[64196]: xfer_data (server to client): failed (Connection reset by peer) with flags 00
Dec  7 15:32:31 fw syslogd: kernel boot file is /boot/kernel/kernel

Are there any known issue with ftp-proxy+pf?
What should we do?