Upgrade complains about locales

I’ve got one unsolved problem https://help.nextcloud.com/t/nextcloud-does-not-display-in-full-featured-browser/78280. I thought an update might be helpful, especially as one theory is that the update did not proceed properly.
This problem has been around beforehand, for at least 2 other successful updates, but it may be relevant, so I have provided the link to my first question.
Installed locales are
en_AU.UTF-8 UTF-8
en_US.UTF-8 UTF-8
the en_US.UTF-8 UTF-8 was installed when this error was first seen but did not solve the problem
problem was previously bypassed by hacking to remove the local check from Nextcloud
While I could just repeat this it may point to other solutions to my first problem.

[/details]

Nextcloud version (eg, 18.0.2): 18.0.4
Operating system and version (eg, Ubuntu 17.04): Linux banksia 4.9.0-3-686-pae #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) i686 GNU/Linux
Apache or nginx version (eg, Apache 2.4.25): Apache2 2.4.38-3+deb10u3
PHP version (eg, 7.1):7.3
The issue you are facing:
Browser complains that correct locale is not installed

Error

Setting locale to en_US.UTF-8/fr_FR.UTF-8/es_ES.UTF-8/de_DE.UTF-8/ru_RU.UTF-8/pt_BR.UTF-8/it_IT.UTF-8/ja_JP.UTF-8/zh_CN.UTF-8 failed

Please install one of these locales on your system and restart your webserver.

Is this the first time you’ve seen this error? (Y/N): N

Steps to replicate it:

  1. Update nextcloud
  2. View in browser

The output of your Nextcloud log in Admin > Logging:
starting at the beginning of the update and running into the start of the next cron job

https://pastebin.com/7xJmuJjh

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?php
$CONFIG = array (
  'instanceid' => 'ocujwoqdsjmo',
  'passwordsalt' => 'qwertyuiop',
  'secret' => 'qwertyuiop',
  'trusted_domains' => 
  array (
    0 => 'www.my_domain.net',
    1 => '192.168.xxx.1',
    2 => 'my_domain.net',
  ),
  'datadirectory' => '/var/www/nextcloud/data',
  'overwrite.cli.url' => 'https://www.my_domain.net/nextcloud',
  'dbtype' => 'mysql',
  'version' => '18.0.3.0',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'oc_admin1',
  'dbpassword' => 'qwertyuiop',
  'installed' => true,
  'mail_smtpmode' => 'smtp',
  'mail_from_address' => 'nextcloud',
'mail_domain' => 'my_domain.net',
  'mail_smtphost' => 'mail.my_domain.net',
  'mail_smtpport' => '25',
  'maintenance' => false,
  'theme' => '',
  'loglevel' => 0,
  'updater.release.channel' => 'stable',
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'mail_sendmailmode' => 'smtp',
  'mail_smtpsecure' => 'tls',
  'mysql.utf8mb4' => true,
  'app_install_overwrite' => 
  array (
    0 => 'files_reader',
    1 => 'files_clipboard',
  ),
);

The output of your Apache/nginx/system log in /var/log/____:
note this is localtime ie UTC +10

192.168.xx.102 - liz [30/Apr/2020:07:12:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7928 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:12:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7928 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:13:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7928 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:13:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7928 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:14:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7928 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:14:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7928 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:15:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 503 7887 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - - [30/Apr/2020:07:15:40 +1000] "GET /nextcloud/index.php/ HTTP/1.1" 503 5113 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:43 +1000] "GET /nextcloud/core/css/guest.css?v=7cfb16bb-0 HTTP/1.1" 200 6834 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:43 +1000] "GET /nextcloud/core/js/files/client.js?v=7cfb16bb-0 HTTP/1.1" 200 6487 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:43 +1000] "GET /nextcloud/core/img/background.png?v=2 HTTP/1.1" 200 36093 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:43 +1000] "GET /nextcloud/core/img/logo/logo.svg?v=1 HTTP/1.1" 200 1021 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:43 +1000] "GET /nextcloud/core/js/dist/main.js?v=7cfb16bb-0 HTTP/1.1" 200 411879 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:44 +1000] "GET /nextcloud/index.php/js/core/merged-template-prepend.js?v=7cfb16bb-0 HTTP/1.1" 503 4819 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:44 +1000] "GET /nextcloud/core/search/js/search.js?v=7cfb16bb-0 HTTP/1.1" 200 2955 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:45 +1000] "GET /nextcloud/core/js/files/fileinfo.js?v=7cfb16bb-0 HTTP/1.1" 200 2156 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:45 +1000] "GET /nextcloud/core/search/js/searchprovider.js?v=7cfb16bb-0 HTTP/1.1" 200 5022 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:45 +1000] "GET /nextcloud/core/img/favicon.ico HTTP/1.1" 200 3963 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
192.168.xx.102 - - [30/Apr/2020:07:15:45 +1000] "GET /nextcloud/core/img/favicon-touch.png HTTP/1.1" 200 3604 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0"
::1 - - [30/Apr/2020:07:15:51 +1000] "OPTIONS * HTTP/1.0" 200 196 "-" "Apache/2.4.38 (Debian) OpenSSL/1.1.1d mod_wsgi/4.6.5 Python/2.7 mod_perl/2.0.10 Perl/v5.28.1 (internal dummy connection)"
::1 - - [30/Apr/2020:07:15:52 +1000] "OPTIONS * HTTP/1.0" 200 196 "-" "Apache/2.4.38 (Debian) OpenSSL/1.1.1d mod_wsgi/4.6.5 Python/2.7 mod_perl/2.0.10 Perl/v5.28.1 (internal dummy connection)"
192.168.xx.102 - liz [30/Apr/2020:07:15:49 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
::1 - - [30/Apr/2020:07:16:01 +1000] "OPTIONS * HTTP/1.0" 200 196 "-" "Apache/2.4.38 (Debian) OpenSSL/1.1.1d mod_wsgi/4.6.5 Python/2.7 mod_perl/2.0.10 Perl/v5.28.1 (internal dummy connection)"
192.168.xx.102 - liz [30/Apr/2020:07:16:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:16:18 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:16:14 +1000] "GET /nextcloud/ocs/v2.php/apps/notifications/api/v2/notifications?format=json HTTP/1.1" 200 1011 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:17:00 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:17:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:17:22 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:17:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:17:54 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:18:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:18:26 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:18:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:18:58 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:19:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:19:30 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:19:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:20:02 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:20:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:20:34 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:20:43 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8235 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:21:06 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 8236 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:21:13 +1000] "PROPFIND /nextcloud/remote.php/dav/files/liz/ HTTP/1.1" 207 1302 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"
192.168.xx.102 - liz [30/Apr/2020:07:21:14 +1000] "GET /nextcloud/ocs/v2.php/apps/notifications/api/v2/notifications?format=json HTTP/1.1" 304 7270 "-" "Mozilla/5.0 (Linux) mirall/2.6.2-1 (Nextcloud)"