You've got these CSS styles that are causing the problem:  html { overflow-y: hidden; height: 100vh; } I was a bit confused, though, because both the CodePen and your post-gazette.com demos behaved identically in Chrome, Safari, and Firefox for me. It sounded like you thought it was only an issue in Firefox and Safari?    ScrollTrigger is totally fine to use on mobile. I'm not sure what you mean by "inconsistent page loading". The main issue on some mobile devices simply has