pfSense WAN IPV6 interface issues with neighbor solicitation being performed every 30 secs

[rvadi]

After upgrading to 2.8.0 I observed that the dpinger kept showing me packet drops consistently around 28-30%, I also observed that pinging through the firewall to an IPv6 host on the internet suffered packet drop issues. When looking at a tcpdump, I observed that everytime the WAN interface would send out IPv6 Neighbor Soliciation messages, around 3 at a time, the pings would start failing, as well as IPv6 connectivity in general, the situation would recover after about 8-9 secs.

I noticed that the interfaces (WAN, LAN) have NDP unreachability detection enabled at 30 secs on the interfaces. I disabled NUD on the interface via the ndp command, and this set the NDP expiration at 24 hours, and the pings and connectivity suffered no drops (I suspect they still will do so when the NDP entry expires, and the interface will send a solicit message, but this is every 24 hours).

I think what I have done is simply a workaround, I think something is not quite right as during the neighbor solicitations and update of the NDP table, the interface stops forwarding traffic.