Full pop-up menu flashes quickly when page loads

I have a standard dropdown menu in which jQuery is used to hide items lifor children. However, when the site loads, elements-elements quickly appear and subsequently disappear (like a quick flash). I do not think that this is generally related to the well-known problem related to unrelated content.

The site is in Hebrew, but it does not affect anything. The site is located here.

If you need HTML + CSS sample and Javascript code, I would love to post it here.

I'm just wondering if anyone has encountered this problem before. I see this in Chrome, and I really have not tested whether this also happens in IE and Firefox.

Thank!

EDIT: HTML / CSS / JS shown below:

HTML:

<ul class="menu">
  <li><a href="#">blah</a>
    <ul class="sub-menu">
      <li><a href="#">blah</a></li>
    </ul>
  </li>
</ul>

CSS

/* NAVIGATION -- level 1 */
ul.menu { float: right; list-style-type: none; font-size: 15px; margin-top: 50px; }
ul.menu > li{ float: right; display: inline; position: relative; margin-left: 30px; }
ul.menu li > a { display: block; color: #5c5d5f; text-decoration: none; border-bottom: solid 1px #9b9a95;  }

ul.menu li:hover > a, ul.menu li a:hover , ul.menu li.current_page_item > a { color: black; }
body.home .current_page_item > a { }
body.home .current_page_item > a:hover { }

/* NAVIGATION -- level 2 */
ul.menu li > div { display: none; width: 157px; height: 171px; margin-right: -10px; position: absolute; opacity:0; background: url(images/subNav_bg.png) no-repeat top right; }

ul.menu li > div span { height: 15px; background: transparent; display: block; } /* used to push down the menu */

JS:

// navigation menu //
// add hasSubMenu to each li that has one //
$('.menu > li').has('ul').addClass('hasSubMenu');

// wrap with <div> //
$('li.hasSubMenu > ul').wrap('<div />');
$('ul.menu li > div').css('display', 'none');
$('ul.menu li > div').prepend('<span></span>');
$('li.hasSubMenu > a').click(function () {
    return false;
});

// add class to <div> for extendedBg //
$('li.extendedBg').find('div').addClass('subBg2');

$('li.hasSubMenu').hover(function () {
    // hover on
    $(this).addClass('hover').find('div').stop().fadeTo("medium", 1, /* when done fading */
        function () {
            $(this).find('div').css('display', 'block');
            //$(this).find('ul').css('display','block');
        }
    );

}, function () {
    // hover off
    $(this).removeClass('hover').find('div').stop().fadeOut();
});