Issue Very weird open_basedir error

[nickb]

Hello there.

I am experiencing the following error:

PHP message: PHP Warning: file_exists(): open_basedir restriction in effect. File(/var/www/vhosts/business.eu/httpdocs/wp-content/upgrade/akismet.4.2.1-giPwTp/) is not within the allowed path(s): (/var/www/vhosts/business.eu/httpdocs/:/tmp/) in /var/www/vhosts/business.eu/httpdocs/wp-admin/includes/class-wp-filesystem-direct.php on line 390

I know what open_basedir is and how it's supposed to work. However, the mentioned path (/var/www/vhosts/business.eu/httpdocs/wp-content/upgrade/akismet.4.2.1-giPwTp/) is within the allowed path (/var/www/vhosts/business.eu/httpdocs/). Am I missing something or is this a bug?