PHP在页面加载时不要获得$ _GET值，但是要重新加载它们

I have this URL:

http://www.origenseguridad.com.mx/SSS/AsignaServicios.php?a=edit&recid=3&TextoResp=Asignar:%20Tipo%20de%20Servicio,%20T%C3%A9cnico,%20Fecha/Hora%20de%20ejecuci%C3%B3n,%20T%C3%A9cnico%20y%20Objeto%20del%20Servicio&TEventosID=3

the code:

if (isset($_GET["a"])) 
{
    print_r($_GET);
} else { 
    echo '$_GET not found';
} 

Calling the page results in $_GET not found

But reloading results in the correct output:

Array ( 
  [a] => edit 
  [recid] => 3 
  [TextoResp] => Asignar: Tipo de Servicio, Técnico, Fecha/Hora de ejecución, Técnico y Objeto del Servicio 
  [TEventosID] => 3 
)

This only happens with scripts in my development directory which is at the same level of my pre-production directory, where it does work as intended ($_GET array the first time the page is called)

I believe it is not an Apache problem because it works on the other directory

.htaccess files are identical in both directories:

# Displaying PHP errors
php_flag display_errors on
php_value error_reporting 6143

I normally rename my development directory to a pre-production status, so people might test the application, but as it is now I can not move forward.

Issue found and lesson remebered.

As I did not get any errors in the error logs, Almost certainly there should be an error in the code.

Ended up that in one of the include files I had written a function to Unset the $_GET array, if the page was not called either from iself or from the Pendings page. The pending list page was "hard" coded to the pre-production directory, so it will only work from there or being called from itself, which was the reason it workwed on reload, clearing the $_GET variable did not cleared the url.

Making the unset function to be aware of the directory structure, cleared out the issue.

Thank's for everybody's help, specially to IMSoP by directing me back to basics