CMS Next and Previous JS working, but repeated headings

Design help CMS
#1

I have used other forum posts to work out the JS for adding a Previous and Next link on my blog posts.

I have added headings too, using other code from previous posts.
BUT I get 2 copies of the heading.

I don’t understand the JS - I just cut and pasted and changed things as required, but obviously there’s something not right here.

Here’s the code I’m using:

<style>#post_list{display: none;}</style>

<script>
  var Webflow = Webflow || [];
  Webflow.push(function () { 
    
    var next_href = $('#post_list .w--current').parent().next().find('a').attr('href');
    var previous_href = $('#post_list .w--current').parent().prev().find('a').attr('href');
    var next_title = $('#post_list .w--current').parent().next().find('a').text();
var previous_title = $('#post_list .w--current').parent().prev().find('a').text();
    
    
    //if last post in list
    if(next_href == undefined) {
      next_href = $('#post_list').children().children().first().find('a').attr('href');
      $('#next_button').fadeOut(); //optional - remove if you want to loop to beginning
    }
    
    //if first post in list
    if(previous_href == undefined) {
      previous_href = $('#post_list').children().children().last().find('a').attr('href');
      $('#previous_button').fadeOut();  //optional - remove if you want to loop to end
    }
    
    //apply hrefs to next / previous buttons
    $('#next_button').attr('href', next_href);
    $('#previous_button').attr('href', previous_href);
    $('#next_title').text(next_title);
$('#previous_title').text(previous_title);
    
  });
</script>

I guess the problem is in the 3rd “paragraph” ???

Here is my public share link: https://preview.webflow.com/preview/jessicas-fabulous-project-570f5e?utm_medium=preview_link&utm_source=designer&utm_content=jessicas-fabulous-project-570f5e&preview=b16a4c3780f1ad56fb149556d01d0b21&pageId=5edfb2299d4d57681fa48c8b&itemId=5edfb235a5e96662188f3258&mode=preview
(how to access public share link)