There is no info on squarespace.com regarding IPv6 support and even squarespace.com does not have any AAAA records present. This leads to the question:
Can my website hosted on Squarespace be reached via IPv6? If so, where should the DNS records point to in order to reach my website?
It is best practice to have an ipv6 address, yet Squarespace does not have an ipv6 address.
Yes, Squarespace does not follow best practice, and no, there is no way to fix it besides to wait for them to update their systems.
It should only affect a very, very small amount of your users who are both (1) on ipv6-native networks and (2) with a malfunctioning NAT.
If you do not have a AAAA record present it is most likely automatically generating a record to the IPv4 server.
Either that or it forces the IPv4 connection on the device attempting the IPv6 connection.
I have only ever experienced issues with having the correct server value set for the IPv4 record and (accidentally) had the IPv6 point to the old server I was using, causing a whole host of issues on certain devices. But, I just deleted the IPv6 record and 24 hours later the change had propagated and it was resolved (I now don't have an IPv6 record declared - but it works swimmingly).
This is what I have experienced with other host sites (not squarespace).
