PHP directives PHP_INI_SYSTEM not working for PHP-FPM
You can edit custom directives for php.ini on the ISPConfig Panel. In php-fpm case when you declare a directive of type PHP_INI_SYSTEM it dosen't apply to system, because you have to edit in the php pool php.ini The problem is when you create a phpinfo file. You can see the value that you configured on the panel, but it's not applying correctly. The value that is applying is the value on php.ini pool.
If you configure a directive type PHP_INI_SYSTEM on a php-fpm hosting, ISPConfig must detect it and not write to fpm conf. In my case it is happening with 'disable_functions' Maybe the easiest way for this issue is to create a new field like 'PHP open_basedir:' (PHP disable_functions:) and when is a php-fpm hosting show that is not configurable at least you configure on the general php.ini.
Server OS: debian Server OS version: Stretch ISPConfig version: 3.1.11