This started out as a question but I finally fingered out why I was getting about 9 “radvd[46842]: sendmsg: Permission denied” log events every minute.
Make sure you disable IPv6 (IPv6 drop done configuration “none”) on every single interface (WAN, LAN, DMZ etc).
I was finding all kinds of ‘high level’ stuff when googling around, even guys that submitted crazy bug reports but thankfully I found this reddit post:
Always check your logs peeps!