I guess then that it is simple , when you are clicking on one tab, the content is being fetched fro server in the mean time you are clicking on another tab and the previous ajax call could not be completed. So the solution would be to disable all tab clicks while your ajax calls are being processed:
$(".your_Tab_class").removeClass('.class_name_assigned_To_click_event');
When the ajax calls have been completed,re-assign the click events based on class name
$('.your_Tab_class').each(function(){
$(this).addClass('.class_name_assigned_To_click_event');
});