reveal() reset when using afterReveal and scrolling fast

How to duplicate: https://jsfiddle.net/9vcytj2b/

Scroll up and down, you'll see that the header text and the footer text keeps animating. `reset` is set to `false` by default so this should not happen. Using `cleanup: true` make it works, but is not friendly when you use `sync()`.

It works as expected when you comment out the `afterReveal` callbacks: https://jsfiddle.net/jxcnb2wp/

The fact that it works correctly without callbacks leave me thinking that there is a bug somewhere in there.