> Any other details I could provide to find the cause of this problem?

Ok, time to file a PR: downgrading parts of ipfilter to

sys/netinet/ip_nat.c r1.35
sys/netinet/ip_nat.h r1.21
sys/netinet/ip_ftp_pxy.c r1.17
sys/netinet/ip_rcmd_pxy.c r1.5

(some arbibtrary collection of versions that make it compile again and backout
the last ip_nat.c changes) fixes my problems (albeit making the ftp proxy
non-functional, so the former test case still does not work, but all others
do).


Martin