Navigation menu - the background on hover behaves strangely

I have a problem with the navigation menu for which I applied pie.js (a library that allows you to have css3 in ie6-8 browsers). It works well at first glance, but if we play a little with the menu, the wrong behavior will increase :( To get this strange behavior, you have to move the cursor a little faster left and right over the drop-down menu in IE8. The function calls js library via j.

$(document).ready(function(){
    if (window.PIE) {
        $('.aahov,ul#menu,ul#menu li ul').each(function(){
            PIE.attach(this);
        });
    }

});

Check this example: http://mainpage.ueuo.com

... and don't forget that only in IE8 browsers ...

Thank x.