My nest updated last night. If I try to enable IPv6 it tries for a moment then the slider just goes back to off...I'm using a Vigor 130 modem.
New firmware stabilised my IPv6, and I no longer had a once-per-day drop out that I usually get.
Unfortunately my network died last night, and I can’t revive it. Everything’s fine at the ONT, but the router just can’t dial out. Factory reset, and can’t get past the PPoE credentials, just pops up saying it doesn’t support VLAN tagging.
Final straw for me, I’m putting my router and points on eBay and buying a system that’s at least semi competent.
I wanted to chip in and share my experience with my 3 nest WiFi routers and by fttp.
I've had one of the nest routers connected directly to the ont for 18 months (the other 2 are connected via mesh). Apart from the odd instance of randomly getting ipv6 up until the PPPOE connection has worked however every few days I'd notice the whole nest network would reboot and it would establish a new PPPOE connection. (It didn't do this if I left the ipv6 toggle off). I got the new firmware update to the nest routers recently and since then not only have I got ipv6 working, the network is rock solid and not reconnecting periodically.
So chuffed to bits now but it has taken Google some time to solve this ipv6 issue.
@Andyg68uk when nest/Google WiFi has ipv6 on but hasn't managed to establish a ipv6 connection it will check every 12 hours. When it does this it reboots the connection, which is why you were getting the drop outs.
That's why I always had it turned off before the latest update.
My WiFi crashed last week and I lost ipv6 for a few days but it came back.