Fixed element with scroll animation not working on tablet

I’m working on a site that uses a couple of scrollable modals. I’ve made them by using a fixed div with overflow scroll. Some of these modals are using scroll animation, they all work fine on desktop but when testing on a tablet (Safari on iPad) they don’t trigger at all. I’m using scroll animations on a number of other elements that is not inside a fixed div parent so I suspect it has something to do with that.

Here is a link to with the setup

Any ideas on how to solve this?

Here is my public share link: LINK
(how to access public share link)