Thanks for reporting it.
I have the impression I also experienced that at some point. I'll check it whenever I have access to a MacBook.

same problem here!

Replace this function in line 561

function MouseWheelHandler(e) {
if(!isMoving()){
// cross-browser wheel delta
e = window.event || e;
var delta = Math.max(-1, Math.min(1,
(e.wheelDelta || -e.deltaY || -e.detail)));

            var activeSection = $('.pp-section.active');
            var scrollable = isScrollable(activeSection);

            //scrolling down?
            if (delta < 0) {
                scrolling('down', scrollable);

            //scrolling up?
            }else {
                scrolling('up', scrollable);
            }


            return false;
        }
     }

for this:

function MouseWheelHandler(e) {
if(!isMoving()){
// cross-browser wheel delta
e = window.event || e;

            var tdelta = (e.wheelDelta || -e.deltaY || -e.detail);
            if(tdelta !== 0){
                var delta = Math.max(-1, Math.min(1, tdelta));
            } else {
                return false;
            }


            var activeSection = $('.pp-section.active');
            var scrollable = isScrollable(activeSection);

            //scrolling down?
            if (delta < 0) {
                scrolling('down', scrollable);

            //scrolling up?
            }else {
                scrolling('up', scrollable);
            }


            return false;
        }
     }

I actually pulled the plug on pagePiling.js, it is just not a viable solution if what, all mac books are buggy.
A solution for me was this:
https://github.com/peachananr/onepage-scroll

i am not posting it to pull away users from your plugin. But I am sure you can let yourself get inspired by their solution. And for the others, use this plugin until u implemented a solution.

I actually pulled the plug on pagePiling.js, it is just not a viable solution if what, all mac books are buggy.

@Jossnaz the bug was not there originally and it seems it has been introduced due to some browsers' update. I had no time to take a look at this bug yet as I have other priorities at the moment.

In any case, if you want a similar solution similar to the one you posted, you can go for fullPage.js (which I also created) if you want a more compatible (IE8 included) reliable and configurable solution than the one you posted.

Solved in pagePiling.js 1.5.3. Please update.