When the server boots:

1. the netif and routing services read correctly information from
2. IPv4 is up for server ip and failover ip
3. /etc/rc.local executes correctly /usr/local/sbin/ipv6-setup-tunnel
4. IPv6 is up
5. jails service kicks, and boot tonderon
6. only the server IPv4 works, other IP are down

To relaunch netif/routing/ipv6 setup restores the connectivity.

Jails should really really really really get dedicated IPs, either through NAT, either through ordering of public IPv4 addresses, either through IPv6-only connectivity.