IPv6 bind to ULA works, but bind to LLA fails

[uselpa]

Good morning
I'm running the latest version of Adguard Home (native, not container) on a Linux computer.

The interfaces of interest are the following:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether bc:24:11:xx:yy:2f brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.22/24 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fd28:redacte1:0:be24:11ff:xxf6:yy2f/64 scope global dynamic mngtmpaddr proto kernel_ra
       valid_lft 6974sec preferred_lft 3374sec
    inet6 2001:redacte2xxxxx:be24:11ff:xxf6:yy2f/64 scope global dynamic mngtmpaddr proto kernel_ra
       valid_lft 6974sec preferred_lft 3374sec
    inet6 fe80::be24:11ff:xxf6:yy2f/64 scope link proto kernel_ll
       valid_lft forever preferred_lft forever

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host proto kernel_lo
       valid_lft forever preferred_lft forever

The following configuration works fine:

dns:
  bind_hosts:
    - 127.0.0.1
    - 10.0.0.22
    - fd28:redacte1:0:be24:11ff:xxf6:yy2f

but if I replace the last line by

    - fe80::be24:11ff:xxf6:yy2f

then the bind for IPv6 on eth0 fails with the following message

[fatal] starting dns server: configuring listeners: listening on udp addr [fe80::be24:11ff:xxf6:yy2f]:53: listening to udp socket: listen udp [fe80::be24:11ff:xxf6:yy2f]:53: bind: invalid argument

although my understanding is that in both cases I respect the constraints ("only on address of each type per interface").

What am I missing?

[uselpa]

Answering my own question - LLA sometimes need a zone index, so adding a suffix of %eth0 to the LLA did the trick.