What PHP.ini settings or configurations could affect the availability of variables from included files on different servers?

The issue could be related to the `auto_globals_jit` directive in the PHP configuration file (php.ini). When this directive is enabled, PHP will only populate the `$_GET`, `$_POST`, `$_COOKIE`, `$_REQUEST`, `$_SERVER`, `$_ENV`, `$_FILES`, `$_SESSION`, and `$_GLOBALS` superglobal arrays when they are accessed. This can lead to variables from included files not being available if they are not explicitly accessed. To solve this issue, you can disable `auto_globals_jit` by setting it to `off` in your php.ini file.

; Disable auto_globals_jit
auto_globals_jit = off