You can disable the PHP override in .htaccess with LiteSpeed Web Server.
php_value and php_flag can be used in Apache configuration or .htaccess to override php.ini settings. However, they are only supported by Apache's mod_php handler, which is deprecated in most of the control panel systems, having been replaced by php-fpm, fastcgi or lsphp. As a result, if you place php_value or php_flag in .htaccess, Apache should return an error. (You can check Plesk's documentation for details).
You could see any one of the following errors:
500 internal server error
503 Invalid command 'php_flag', perhaps misspelled or defined by a module not included in the server configuration. The following error can be found in the domain error log in Domains > example.com > Logs: /var/www/vhosts/example.com/httpdocs/.htaccess: Invalid command 'php_value', perhaps misspelled or defined by a module not included in the server configuration
/var/www/vhosts/example.com/httpdocs/.htaccess: Invalid command 'php_flag', perhaps misspelled or defined by a module not included in the server configuration
/var/www/vhosts/example.com/httpdocs/.htaccess: RewriteRule: bad flag delimiters
/var/www/vhosts/example.com/public_html/.htaccess: Invalid command 'suPHP_ConfigPath', perhaps misspelled or defined by a module not included in the server configuration.
LiteSpeed Web Server uses lsphp, which supports php_value and php_flag usage in .htaccess. You can use these and LSWS will not return a 500 error. LSWS is more tolerant than Apache of these PHP overrides.
In some cases, you may want to disable such PHP overrides in .htaccess for LiteSpeed as well. There is a dedicated Apache directive DisablePhpOverride htaccess, which can be used at the server level httpd.conf to achieve this.
For example, on Plesk, create a file named DisablePhpOverrideLiteSpeed.conf in the following directory, depending upon your system:
/etc/httpd/conf.d//etc/apache2/conf.d//etc/apache2/conf-enabled
This DisablePhpOverrideLiteSpeed.conf file should contain the following:
<IfModule LiteSpeed> DisablePhpOverride htaccess </IfModule>