Got these with a recent (yesterday) netbsd-4 kernel, when using
ipnat(8):

Sep 29 19:17:03 zion sudo:     stix : TTY=ttyp2 ; PWD=/export/home/stix ; USER=root ; COMMAND=/usr/sbin/ipnat -l
Sep 29 19:17:13 zion /netbsd: Data modified on freelist: word 3 of object 0xc1df2080 size 36 previous type bar (0xc1e0f200 != 0xdeadbeef)
Sep 29 19:17:43 zion /netbsd: Data modified on freelist: word 3 of object 0xc1dbfdc0 size 36 previous type bar (0xc1f51e00 != 0xdeadbeef)

I've also noticed that NAT RDR sessions don't appear to have ever
been cleaned up. I have a redirect rule to do transparent proxying
through squid. This was working fine before my last update.

ksh$ sudo ipnat -l | grep RDR | wc -l
    2168

Should I send-pr?

-- 
Paul