Hey Erous,
This sounds like more of a bug and not something that we would be able to troubleshoot over the forums unfortunately. If you have IPv6 enabled in-game and you’re still seeing an IPv6 Home connection, then that means the IPv6 World connection should work as long as it’s configured correctly on the server side.
There were changes to how world servers are hosted with Shadowlands, so it’s possible that IPv6 is not working properly in every situation due to these changes. Hopefully that is something that our QA team and WoW engineers can take a look at and get cleared up.
I’d recommend reporting this over on the #support:bug-report forums or do a search there to see if anyone else has reported similar behavior. IPv6 is not used very widely so other reports may be sparse, but the more reports the better.