Connection closed when npf restarting with rules in non-default group

[Frédéric Fauberteau <triaxx%NetBSD.org@localhost>]

Consider the nfp rule definitions below.

    group default {
      block all apply "log"
      # Localhost loop
      pass final on lo0 all
      # IPv6 ICMP
      pass final family inet6 proto ipv6-icmp all
      # IPv4 pings
      pass in family inet4 proto icmp icmp-type echo all
      # DHCP
      pass in family inet4 proto udp from any port bootps to any port 
bootpc
      pass in family inet6 proto udp from any to any port 
"dhcpv6-client"
      # SSH
      pass stateful in final family inet4 proto tcp to $ext_ip4 port ssh
      pass stateful in final family inet6 proto tcp to $ext_ip6 port ssh
      # Established outgoing connections
      pass stateful out final all
    }

There is no problem when npf is restarted with the command: 'service npf 
restart'

Now consider the same rules using a dedicated group.

    group "external" on wm0 {
      # SSH
      pass stateful in final family inet4 proto tcp to $ext_ip4 port ssh
      pass stateful in final family inet6 proto tcp to $ext_ip6 port ssh
    }

    group default {
      block all apply "log"
      # Localhost loop
      pass final on lo0 all
      # IPv6 ICMP
      pass final family inet6 proto ipv6-icmp all
      # IPv4 pings
      pass in family inet4 proto icmp icmp-type echo all
      # DHCP
      pass in family inet4 proto udp from any port bootps to any port 
bootpc
      pass in family inet6 proto udp from any to any port 
"dhcpv6-client"
      # Established outgoing connections
      pass stateful out final all
    }

Restart the nfp service closes the SSH connection.