Squarespace 7.1 Parallax Jitters

Site URL: https://thelandcollaborative.squarespace.com

Hi All,

I've been through the many posts here about Parallax on Squarespace 7.1. I've tried about 5 different versions (all the issues are in the forums). The parallax is working, but the jitters are terrible when you scroll up. So far, I haven't found a fix for this. Is it possible to get any of the experts on here to commit to figuring it out?  The website is: https://thelandcollaborative.squarespace.com.

I'm using this in the site-wide code injection box: 

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/scrollax@1.0.0/scrollax.min.js"></script>
<script>
  $('.has-background').attr('data-scrollax-parent', 'true');
  $('.has-background .section-background').attr('data-scrollax', 'properties: { translateY: "100%" }');
  $.Scrollax();
</script>
<style>
  .has-background {overflow: hidden;}
</style>

Thank you!