Scroll triggered transitions don't work in IE 11 (mobile)

I’ve been doing some testing of a site I’m building an I’ve noted that transitions that are triggered based on scrolling don’t work on IE 11 on Windows Phone 8.1. I’m using a Nokia Lumia 620 to do my testing. Is this an issue others have had?

Here’s a preview of the site - Webflow - Alteroo

onScroll triggers are deactivated for all mobiles (onscroll is a hard thing to achieve without bugs on mobile) so it’s not going to work on any smartphone or tablet, except the one displaying a big screen, the desktop version (like MS Surface pro).