Description:
------------
When FilesystemIterator iterates through folder with many files, it doubles file entries at 65535th and, more generally, 65535*n+(n-1) positions (131071,196607...).

...
65533.txt
65534.txt // ok
65534.txt // omg what happened with my file system, is it broken? But chkdsk shows nothing bad. Oh well, it's just iterator...
65535.txt 
65536.txt 
...


7.0.0 and later versions work fine.

Test script:
---------------
1) to generate many files in one folder use batch like
for /l %a in (1 1 200000) do type nul > "%a.txt"

2) 
$path = 'd:\pathtoyour\folder';
$items = new FilesystemIterator($path,FilesystemIterator::CURRENT_AS_PATHNAME);
$n = 0;
$name = '';
foreach ($items as $item)
{
	$name_prev = $name;
	$name = basename($item);
	$n++;
	if ($name == $name_prev)
		echo "DUPILCATE ENTRY FOUND AT $n: $name <br>";
}