Xiaomi Router 3G (mir3g) with OpenWrt 19.07.1 IPv6 issue

I do not get it, when i do

firstboot

The default file

/etc/config/network

has configuration for wan6

I then change the protocol ONLY to PPPoE in Luci > Interfaces > WAN and enter the login and password. I do nothing else. Save and apply.

OpenWrt then for some weird reason creates a virtual grayed out WAN_6 entry on Luci.

There is no such entry as WAN_6 in the config file.
It cannot be edited by normal means in Luci.

My question is, what is wrong with the default wan6 entry in the /etc/config/network

Why doesn't OpenWrt create the config under the existing wan6 entry in the /etc/config/network file?

If this is not a bug, then I have no idea what a bug is.

I mean, I have done some tinkering with OpenWrt for many years now, this is very familiar to me.

I was able to get around the grayed out WAN_6 by following method:

I deleted the wan6 entry and added the below instead:

config interface 'wan_6'
	option ifname '@wan'
	option proto 'dhcpv6'
	option reqprefix 'auto'
	option reqaddress 'try'

And then it looks like this:

As you can see, the ISP issues an IPv6 address to the router.

But to the outside world, the router has no IPv6. I checked on all sites:

Marginaal 2020-02-28 011145