WP upgrade is failing after update to WP 6.4.2 due to HyperDB

[lubo-makky]

We are using HyperDB for long time and it has been mostly smooth experience so far. However, after upgrading to WordPress 6.4.2 we are expriencing database issues when running WP updates of core, plugins, themes and/or translations via WP Admin.

Our db-config.php did not change and only way of upgrading now is to temporarily switch HyperDB off by removing it from wordpress root dir.

Maybe somebody else also run into this issue and might have any insights?

Thank you.

Error example

PHP Fatal error:  Uncaught TypeError: mysqli_get_server_info(): Argument #1 ($mysql) must be of type mysqli, null given in wordpress/wp-includes/class-wpdb.php:4158
Stack trace:
#0 wordpress/wp-includes/class-wpdb.php(4158): mysqli_get_server_info(NULL)
#1 wordpress/wp-includes/update.php(78): wpdb->db_server_info()
#2 wordpress/wp-admin/includes/class-wp-upgrader.php(844): wp_version_check(Array)
#3 wordpress/wp-admin/includes/class-plugin-upgrader.php(392): WP_Upgrader->run(Array)
#4 wordpress/wp-admin/update.php(51): Plugin_Upgrader->bulk_upgrade(Array)
#5 {main}
  thrown in wordpress/wp-includes/class-wpdb.php on line 4158