We can see the issue before, and the fix after upgrade as well as the upgrade itself.
=> Setting as verified

root@f:~# apt-cache policy dns-root-data bind9; systemctl restart named; sleep 5s; systemctl status named; apt install -y dns-root-data/$(lsb_release -cs)-proposed; apt-cache policy dns-root-data bind9; systemctl restart named; sleep 5s; systemctl status named;
dns-root-data:
  Installed: 2019052802
  Candidate: 2023112702~ubuntu0.20.04.1
  Version table:
     2023112702~ubuntu0.20.04.1 500
        500 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
 *** 2019052802 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
        100 /var/lib/dpkg/status
bind9:
  Installed: 1:9.16.1-0ubuntu2.16
  Candidate: 1:9.16.1-0ubuntu2.16
  Version table:
 *** 1:9.16.1-0ubuntu2.16 500
        500 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
        100 /var/lib/dpkg/status
     1:9.16.1-0ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
● named.service - BIND Domain Name Server
     Loaded: loaded (/lib/systemd/system/named.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2024-02-05 10:17:33 UTC; 5s ago
       Docs: man:named(8)
   Main PID: 1615 (named)
      Tasks: 14 (limit: 38246)
     Memory: 29.5M
        CPU: 59ms
     CGroup: /system.slice/named.service
             └─1615 /usr/sbin/named -f -u bind

Feb 05 10:17:33 f named[1615]: zone 255.in-addr.arpa/IN: loaded serial 1
Feb 05 10:17:33 f named[1615]: zone 127.in-addr.arpa/IN: loaded serial 1
Feb 05 10:17:33 f named[1615]: all zones loaded
Feb 05 10:17:33 f named[1615]: running
Feb 05 10:17:33 f named[1615]: managed-keys-zone: Key 20326 for zone . is now trusted (acceptance timer complete)
Feb 05 10:17:33 f named[1615]: resolver priming query complete
Feb 05 10:17:33 f named[1615]: checkhints: b.root-servers.net/A (170.247.170.2) missing from hints
Feb 05 10:17:33 f named[1615]: checkhints: b.root-servers.net/A (199.9.14.201) extra record in hints
Feb 05 10:17:33 f named[1615]: checkhints: b.root-servers.net/AAAA (2801:1b8:10::b) missing from hints
Feb 05 10:17:33 f named[1615]: checkhints: b.root-servers.net/AAAA (2001:500:200::b) extra record in hints
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Selected version '2023112702~ubuntu0.20.04.1' (Ubuntu:20.04/focal-proposed [all]) for 'dns-root-data'
The following packages will be upgraded:
  dns-root-data
1 upgraded, 0 newly installed, 0 to remove and 9 not upgraded.
Need to get 5308 B of archives.
After this operation, 0 B of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 dns-root-data all 2023112702~ubuntu0.20.04.1 [5308 B]
Fetched 5308 B in 0s (23.6 kB/s)        
debconf: delaying package configuration, since apt-utils is not installed
(Reading database ... 19204 files and directories currently installed.)
Preparing to unpack .../dns-root-data_2023112702~ubuntu0.20.04.1_all.deb ...
Unpacking dns-root-data (2023112702~ubuntu0.20.04.1) over (2019052802) ...
Setting up dns-root-data (2023112702~ubuntu0.20.04.1) ...
dns-root-data:
  Installed: 2023112702~ubuntu0.20.04.1
  Candidate: 2023112702~ubuntu0.20.04.1
  Version table:
 *** 2023112702~ubuntu0.20.04.1 500
        500 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     2019052802 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
bind9:
  Installed: 1:9.16.1-0ubuntu2.16
  Candidate: 1:9.16.1-0ubuntu2.16
  Version table:
 *** 1:9.16.1-0ubuntu2.16 500
        500 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
        100 /var/lib/dpkg/status
     1:9.16.1-0ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
● named.service - BIND Domain Name Server
     Loaded: loaded (/lib/systemd/system/named.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2024-02-05 10:17:42 UTC; 5s ago
       Docs: man:named(8)
   Main PID: 1729 (named)
      Tasks: 14 (limit: 38246)
     Memory: 29.5M
        CPU: 50ms
     CGroup: /system.slice/named.service
             └─1729 /usr/sbin/named -f -u bind

Feb 05 10:17:42 f named[1729]: command channel listening on ::1#953
Feb 05 10:17:42 f named[1729]: managed-keys-zone: loaded serial 10
Feb 05 10:17:42 f named[1729]: zone 255.in-addr.arpa/IN: loaded serial 1
Feb 05 10:17:42 f named[1729]: zone 127.in-addr.arpa/IN: loaded serial 1
Feb 05 10:17:42 f named[1729]: zone 0.in-addr.arpa/IN: loaded serial 1
Feb 05 10:17:42 f named[1729]: zone localhost/IN: loaded serial 2
Feb 05 10:17:42 f named[1729]: all zones loaded
Feb 05 10:17:42 f named[1729]: running
Feb 05 10:17:42 f named[1729]: managed-keys-zone: Key 20326 for zone . is now trusted (acceptance timer complete)
Feb 05 10:17:42 f named[1729]: resolver priming query complete