I can't reproduce this locally. See below. Is there anything extra special about this environment?
(bionic-amd64)root@nosferatu:~# debconf-show debconf * debconf/frontend: Readline debconf-apt-progress/title: debconf-apt-progress/media-change: debconf-apt-progress/info: debconf-apt-progress/preparing: * debconf/priority: high (bionic-amd64)root@nosferatu:~# apt-get purge tzdata && rm /etc/timezone [...] Purging configuration files for tzdata (2019b-0ubuntu0.18.04) ... (bionic-amd64)root@nosferatu:~# apt-get install tzdata Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: tzdata 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/190 kB of archives. After this operation, 3106 kB of additional disk space will be used. Preconfiguring packages ... Configuring tzdata ------------------ Please select the geographic area in which you live. Subsequent configuration questions will narrow this down by presenting a list of cities, representing the time zones in which they are located. 1. Africa 3. Antarctica 5. Arctic 7. Atlantic 9. Indian 11. SystemV 13. Etc 2. America 4. Australia 6. Asia 8. Europe 10. Pacific 12. US Geographic area: [...] (bionic-amd64)root@nosferatu:~# apt-get purge tzdata && rm /etc/timezone [...] Purging configuration files for tzdata (2019b-0ubuntu0.18.04) ... (bionic-amd64)root@nosferatu:~# DEBIAN_FRONTEND=noninteractive apt-get install tzdata Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: tzdata 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/190 kB of archives. After this operation, 3106 kB of additional disk space will be used. Preconfiguring packages ... Selecting previously unselected package tzdata. (Reading database ... 10885 files and directories currently installed.) Preparing to unpack .../tzdata_2019b-0ubuntu0.18.04_all.deb ... Unpacking tzdata (2019b-0ubuntu0.18.04) ... Setting up tzdata (2019b-0ubuntu0.18.04) ... Current default time zone: 'Etc/UTC' Local time is now: Fri Sep 20 09:20:00 UTC 2019. Universal Time is now: Fri Sep 20 09:20:00 UTC 2019. Run 'dpkg-reconfigure tzdata' if you wish to change it. (bionic-amd64)root@nosferatu:~# ** Changed in: tzdata (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1830495 Title: tzdata noninteractive mode is being ignored To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/tzdata/+bug/1830495/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs