Description:
------------
Hello, 

iam working on an diskstation by synergy connected with an windows domain ... 
while creating an symfony project ive got a failure message shown me that .env coulnd read. 

ive tested some scripts and yeah ... php has an problem there ... 

$filename = this file is on an network share assign to Z:
var_dump(is_readable($filename)); = is false ... dunny why
var_dump(is_writeable($filename)); = is false, too 
var_dump(is_dir($filename)); = is false, too
var_dump(file_exists($filename)); = is true
var_dump(file_get_contents($filename)); = read file content and display it

In Process Monitor ive recorded what happend while running the test script (with sleep 10 seconds to see that happend where) 
https://gist.github.com/privatehosting/3dd6876ffe4fc46100089d64d39171b2 

Please excuse my English



Test script:
---------------
<?php
    $filename = "Z:\Programmierung\php_pilichiewicz_cms/.env";
    var_dump($filename);
    sleep(10);
    var_dump(is_readable($filename));
    sleep(10);
    var_dump(is_writeable($filename));
    sleep(10);
    var_dump(is_dir($filename));
    sleep(10);
    var_dump(file_exists($filename));
    sleep(10);
    var_dump(file_get_contents($filename));
?>

Expected result:
----------------
is_readable & is_writeable & is_dir should be true if file exists

Actual result:
--------------
is_readable & is_writeable & is_dir are false