IPv6 over IPv4 Tunneling Option
Since 2.3 I have noticed that the "IPv6 over IPv4 Tunneling" option in Advanced -> Networking does not retain the IP when entered. You can put in an IP, click save, refresh the page and the IP is no longer listed but the check mark remains.
Fix #6381 ipv6nat_ipaddr
(cherry picked from commit f489cfdbd4705578ee290b9df5bafe86efddbca8)