seem wrong with me

[justmd5]

now time is :

php -r "echo date('Y-m-d H:i:s'),PHP_EOL;"

2017-02-15 09:52:42

php -r "echo time(),PHP_EOL;" 

1487123624

here is the code ：

require  __DIR__."/vendor/autoload.php";
$m = new \Moment\Moment("2017-02-21 09:40:22", 'PRC');
\Moment\Moment::setLocale('zh_CN');
echo $m->calendar(),PHP_EOL;

result is:
本周二 09:40
but the result should be "下周二"，please have a look，thanks！

[fightbulc]

Can you check what's going wrong? I don't speak any Chinese.