Well, best time to prompt a crapbot to draw it.

I have that conf: /etc/sysctl.d/01-ipv6.conf

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

But that falls under your exception. It seems to me that IPv6 causes more problems than it solves.