php_admin_value defines a setting that cannot be overridden. The second line is ignored because it is attempting to override the disable_function set earlier.

disable_functions is a comma-separated list of functions. Your configuration should read
  php_admin_value[disable_functions] = curl_init,curl_close

http://php.net/manual/en/ini.core.php#ini.disable-functions

php_admin_value[disable_functions] = leak                                                                                                     
php_admin_value[disable_functions] = phpinfo                                                                                                  
php_admin_value[disable_functions] = exec
<?php
error_reporting(E_ALL);
phpinfo();

Warning: phpinfo() has been disabled for security reasons in /home/www/info.php on line 3

Could you check it first, please?

reproducible on 7.0.5 CLI as well:

php -n -d "disable_functions=phpinfo" -d "disable_functions=exec" -r "phpinfo();echo exec('ls');" | grep disable_

disable_functions => exec => exec

Disregard my last comment.

If you do
  php_admin_value[disable_functions]=sin
  php_admin_value[disable_functions]=cos
  php_admin_value[disable_functions]=tan
what does phpinfo() say, what does ini_get("disable_functions") return, and which of those functions do/do not work?

<?php
error_reporting(E_ALL);
echo 'disable_functions=', ini_get('disable_functions'), "\n";
echo 'sin(0)=', sin(0), "\n";
echo 'cos(0)=', cos(0), "\n";
echo 'tan(0)=', tan(0), "\n";


 disable_functions=sin sin(0)=                                                                                                              
   Warning: sin() has been disabled for security reasons in /home/www/v2.6.5/info.php on line 4                                               
   cos(0)=                                                                                                                                    
   Warning: cos() has been disabled for security reasons in /home/www/v2.6.5/info.php on line 5                                               
   tan(0)=                                                                                                                                    
   Warning: tan() has been disabled for security reasons in /home/www/v2.6.5/info.php on line 6

No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Re-Opened". Thank you.

This case has been reopened as of 8/29/2019 @ 1:01AM. Please comment any new information here. Otherwise, send an email directly requinix@php.net.