CARP misbehaving on RPi2+ / RPI3

[Greywolf <relayer%gmail.com@localhost>]

Greetings; I have a couple RPi that I will refer to here as 'thing1'
and 'thing2'.  Both are running evbarm-earmv7h, NetBSD 10-BETA.

thing1: rpi2+
/etc/ifconfig.carp0:
create
vhid 1
advbase 21
advskew 2
carpdev usmsc0
pass aPassword
172.21.12.2/23
up

thing2: rpi3
/etc/ifconfig.carp0:
create
vhid 1
carpdev usmsc0
pass aPassword
172.21.12.2/23
up


thing1 comes up with CARP in BACKUP mode, as expected.
thing2 comes up and enables CARP, and all is relatively well except
that no other host on the network can ping the VIP.

Is this a limitation of the RPi hardware, or am I doing something wrong?

My intent was to use these two as a VIP'd nameserver.

-- 
--*greywolf;