Mullvad connecting to IPv6

[p1r473]

Hi @ArcherN9
I followed your guide and I got Pihole, Mullvad, and PiVPN all working. Thank you VERY much for it.

Except, once in a while, I end up connecting to Mullvad over IPv6. This somehow breaks some things, and all in all, I dont use IPv6, but disabling IPv6 on the Pi or router breaks the VPN connection entirely

Any idea why it occasionally connects to Mullvad via IPv6, or how to prevent it?
Ideally I want to not use IPv6 anywhere, and not connect to Mullvad on IPV6. I can't disable it without issues, though.

So far, a reboot, and reconnecting to Mullvad over IPv4 fixes the issue. I'd like to fix the root cause and prevent any IPV6 connections (but also no leaks)

Note the IPv6 address:

curl https://am.i.mullvad.net/connected

You are connected to Mullvad (server XXXX-wireguard). Your IP address is XXX:XXXXXXXX:XX::XXXX

Somehow connecting over IPv6 starts breaking things, such as my PiHole resolution, by breaking my upstream connection.

nslookup google.ca 127.0.0.1
Server:         127.0.0.1
Address:        127.0.0.1#53

** server can't find google.ca: SERVFAIL