Isotope will cause bubbling in the script - in reference to your hover effects bind them with using ON. http://api.jquery.com/on/
$("p").on("hover", function(){
alert( $(this).text() );
});
Although - I see you are setting it via the css. - You can loop loop through the isotope element and append the class specifically to ensure it works. Or you could use the above hover function to append or remove the class.
http://isotope.metafizzy.co/docs/extending-isotope.html
$('#container').isotope({
itemSelector: '.element',
itemPositionDataEnabled: true
})
// log position of each item
.find('.element').each(function(){
var position = $(this).data('isotope-item-position');
//APPEND required class here. ensure its on the elements
console.log('item position is x: ' + position.x + ', y: ' + position.y );
});