ICL_LANGUAGE_CODE and polylang

I’ve update my themes and plugin and now i’ve some problem with ICL_LANGUAGE_CODE in functions.php.

If in functions.php i write a debug line like this one:

?>

LANGUAGE CODE:<?php var_dump(ICL_LANGUAGE_CODE); ?>

<?php

System return me correctly the language code but if i insert that constant inside a filter (see below) it doesn’t take the actual language of the website.

How can i resolve this problem?

Thank you
Vincenzo

add_filter( ‘wpcf7_validate_nazioni’, ‘custom_nazioni_validation_filter’, 10, 2 );
function custom_nazioni_validation_filter( $result, $tag ) {
global $testo_campo_obbligatorio;
$tag = new WPCF7_Shortcode( $tag );

if(!isset($_POST[‘nazione’]) || $_POST[‘nazione’] == “”){
$tag->name = ‘nazioni’;
$result->invalidate( $tag, ICL_LANGUAGE_CODE );
}
return $result;
}