This uses inconsistant shorthand and causes Skrollr to error and stop working.
If you look in the developer tools, you'll see the error Uncaught Can't interpolate between "{?}px {?}px {?}px {?}px" and "{?}px"
in the Console
<div class="box"
data-0000="padding: 0px 0px 0px 0px;"
data-2000="padding: 50px;"
></div>