6.0-RC1 IPv6 losing local subnet route

[Craig Boston]

[ I'm not subscribed to net@ so please copy me! ]

It's been a while since I've used IPv6 (was on 4.x), so it's possible
I'm doing something wrong, but it seems like this should work.

Setup: A simple network with 3 or 4 FreeBSD boxes running 6.0-RC1.  No
contact with the outside world, no routers, just an ethernet switch.  No
rtadvd or rtsol -- everything is staticly configured.

[SAMPLE]
Box1:
ifconfig em0 inet6 2002:abcd:ef01:5555::20/64

Box2:
ifconfig em1 inet6 2002:abcd:ef01:5555::30/64

At first everything works like it should.  However, after a seemingly
random amount of time one of the machines loses its route for the local
network.

netstat -rn before it goes bad:
Internet6:
Destination                       Gateway                       Flags      Netif
::1                               ::1                           UH          lo0
2002:abcd:ef01:5555::/64          link#1                        UC          em0
2002:abcd:ef01:5555::20           00:07:e9:ab:cd:34             UHL         lo0
2002:abcd:ef01:5555::30           00:07:e9:ab:cd:65             UHLW        em0

and after:
Internet6:
Destination                       Gateway                       Flags      Netif
::1                               ::1                           UH          lo0
2002:abcd:ef01:5555::20           00:07:e9:ab:cd:34             UHL         lo0
2002:abcd:ef01:5555::30           00:07:e9:ab:cd:65             UHLW        em0

You can still ping6 any neighbors that have already been discovered, but
any new ones just return "No route to host".

Happens on every machine I've tested so far (but they were all running
6.0).  Sometimes takes an hour or two, sometimes less.

Bug or feature?

Thanks,
-- Craig