So, I have kinda seen this for a little while but haven't had time to
A way I can reproduce this.
I have a laptop with iwn0 and bge0, with trunk0
$ cat /etc/hostname.trunk0
trunkport bge0 trunkport iwn0 trunkproto failover
My router is OpenBSD running rtadvd. If that machine panicks, even
after I restart it, IPv6 is broken on my laptop until I:
# ifconfig trunk0 destroy
# sh /etc/netstart trunk0
All non-OpenBSD devices on the network start working with IPv6 after the
router comes back up.
I'll try to test this further when I have time, but when the router is
down, people yell. :)