Macbook, OpenVPN, and IPv6 Weirdness

[the wafflator]

I've got a very strange issue that I can't figure out. I've got a couple devices at one location (Location A) that I am using OpenVPN to connect to another location (Location B). So far I've set up four devices at Location A:

1. An Android phone. Works as expected.
2. A Chromebook, using the Android OpenVPN app. Works as expected.
3. A Windows 10 PC. Works as expected.
4. A Macbook Air. It connects to the VPN, confirmed by checking the logs on the OpenVPN server. It can access stuff on Location B's local network. But internet traffic does not seem to be going over the VPN. It seems to still be going out from Location A. Even more weird, if I google "what is my IP" I get an IPv6 address. If I do that while connected to the VPN on the other devices, I get Location B's public IPv4 address, as expected.

What the heck is going on here? How is the macbook appearing to the outside world on an IPv6 address when no other devices are?

 

[Cmustang87]

Turn off IPv6 for the OpenVPN on the Macbook. Sites like Google etc. are available over IPv6 and it sounds like some of this traffic is 'leaking'.