remove_polylang_mandatory_cookie.php

<?php
function rocket_remove_polylang_mandatory_cookies( $cookies ) {
	$cookies = array_flip( $cookies );

	unset( $cookies['pll_language'] );

	return array_flip( $cookies );
}
add_filter( 'rocket_cache_mandatory_cookies', 'rocket_remove_polylang_mandatory_cookies', 11 );