This selector fails with the following html structure:

<ul id="root">
    <ul id="nested">
        <li></li>
    </ul>
    <li></li>
    <li></li>
</ul>

The QSA version works fine.

But if I change the container to a superior level (i.e. body) this works fine:

$('body').find(':not(#nested) > li')

It seems this selector does not work with direct children.

Here is a jsfiddle that illustrates the bug : http://jsfiddle.net/ngryman/tsw4b/.

It fails for any version of jQuery.

Thanks.