Jquery nav bar hider script using lot of resources and generating console errors on Jquery 3 beta

I have this navbar hider script for handheld devices:

function bindNavUp() {
  var lastScrollTop = 0, delta = 5;
  $(window).on('scroll', function() {
    var st = $(this).scrollTop();

    if(Math.abs(lastScrollTop - st) <= delta) {
      retu;
    };

    if (st > lastScrollTop) {
      // downscroll code
      $('header.main').css('top','-50px').hover();
    }
    else {
      // upscroll code
      $('header.main').css('top','0');
    };
    lastScrollTop = st;
  });
};
function unbindNavUp() {
  $(window).unbind('scroll');
};
function handleNavUp() {
  if ($(window).width() < 1600) {
    bindNavUp();
  }
  else {
    unbindNavUp(); 
  };
};
$(document).ready(function() {
  var timer;
  $(window).on('load resize scroll', function() {
    clearTimeout(timer);
    timer = setTimeout(function() {
      handleNavUp();  
    }, 100);
  });
  handleNavUp();
});

The problem with this is that upscrolling works great with Jquery 2.2.1:

https://jsfiddle.net/Lanti/03kw42o1/4/

But not with Jquery 3 Beta 1, the hidden elements of the header not coming back (I use Firefox latest):

https://jsfiddle.net/Lanti/03kw42o1/5/

Also, with Jquery 3 I've got lots of console errors: TypeError: c is null

I haven't got any of this with Jquery 2.2.1, but both cases I also feel a huge performance drop when this script is applied to the normal, non-responsive view of my design.