NC18.0.4.2 permanent Internal Server Error on Docker

Hello nextcloud community!

Currently I have an instance of Nextcloud running under Docker and it was working fine for quite some time. Doker image that i’m using is providen by LinuxServer and it has regular updates.

Few days ago i’ve found my Nextcloud unaccessible, DAV was either working. the only response from nc web server is this one:

Internal Server Error

The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log.

After some log digging, it seems like at some point, upload for one of the users failed and now server is only reporting previous issue with status 500. The main issue appers to reside in PHP server and specifically config file, but that file had no changes after it’s initial setup.

nginx.log

2020/05/26 00:09:11 [error] 344#344: *39 FastCGI sent in stderr: "PHP message: PHP Parse error:
 syntax error, unexpected ''instanceid'' (T_CONSTANT_ENCAPSED_STRING), expecting ')' in /config/www/nextcloud/config/config.php on line 6" while reading upstream, client: 192.168.10.1, server: _, request: "GET / HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "nextcloud.example.domain"

php.conf

<?php
$CONFIG = array (
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'datadirectory' => '/data',
  'instanceid' => 'xxxxx',
  'passwordsalt' => 'xxxxx',
  'secret' => 'xxxxx',
  'trusted_domains' =>
  array (
    'nextcloud.example.domain',
  ),
  'dbtype' => 'mysql',
  'version' => '18.0.4.2',
  'overwrite.cli.url' => 'https://nextcloud.example.domain',
  'dbname' => 'nextcloud',
  'dbhost' => '192.168.11.22:3306',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'nextcloud',
  'dbpassword' => 'xxxxx',
  'installed' => true,
  'twofactor_enforced' => 'false',
  'twofactor_enforced_groups' =>
  array (
  ),
  'twofactor_enforced_excluded_groups' =>
  array (
  ),
  'maintenance' => false,
  'theme' => '',
  'loglevel' => 2,
  'tempdirectory' => '/data/tmp'
);

nginx.conf
php error.log
nextcloud.log

I hope someone can help me with this issue because server already has 1tb of encrypted data.
Thank you all!