Comment 5 for bug 2039374

Yes you're right it is abnormal.
What's going on is that I had set the sysctl parameter net.ipv6.conf.lo.disable_ipv6=1, which of course disables the IPv6 loopback.

But it exhibits a curious behavior where if there is an active IPv6 regular (non-loopback) interface with an IPv6 address and network connection, then connection attempts to ::1 seem to hang and timeout, but if there is no active IPv6 at all, then connections to ::1 will instantly fail with a "cannot assign requested address".

I guess this didn't work this way before 22.04.
There are no IPv6 firewall rules for the loopback.
I haven't seen any other daemons with issues from this. Maybe they are using IPv4 for loopback?