"tcpflags 0x18<PUSH,ACK>; tcp_do_segment" kernel messages

I cvsupped my -CURRENT laptop last night and have been building ports
today.  When I checked the dmesg there were lots of messages similar to:

TCP: [204.152.184.73]:21 to [10.0.10.13]:65159] tcpflags 0x18<PUSH,ACK>;
tcp_do_segment: FIN_WAIT_2: Received data after socket was closed,
sending RST and removing tcpcb

The machine's uname:
FreeBSD muon.draftnet 7.0-CURRENT FreeBSD 7.0-CURRENT #1: Sun Aug 5
23:58:47 BST 2007 brucec_at_muon.draftnet:/usr/obj/usr/src/sys/INSPIRON
amd64

The laptop is connected to a machine running a month-old -CURRENT;
it's running NAT via PF to my LAN using if_bridge.  Apart from removing
unused drivers, the laptop's kernel configuration has HZ set to 100 and
I've added PF.

--
Bruce Cran