Jquery validator doesn't validate homonymous input field (input array) [duplicate]

I have a form with many fields with the same name, this will be an array input for PHP.

<input type="text" name="user[]" required />

Unfortunately it seems that Jquery validator, used on entire form, ignores consecutive inputs with the same name and it validate only the first one.

Take a look at this example:

<form class="validation-form">
    <lable>User1</lable>    
    <input type="text" name="user[]" required /><br>
    <lable>User2</lable>
    <input type="text" name="user[]" required /><br>
    <button class="submit-form">submit</button>
</form>

https://jsfiddle.net/xr5a03qf/

If you push on submit, you will se only the first required field is checked, if you fill just the first one, the form will be submitted as valid.

Is this a bug?