Steps to reproduce

1. Add the following code in a multi line text custom field configured with the Default Text Renderer:

   <script>
     (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
     (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
     m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
     })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
   
     ga('create', 'UA-111111-1', 'auto');
     ga('require', 'linkid', 'linkid.js');
     ga('require', 'displayfeatures');
     ga('send', 'pageview');
   

Expected results

The code will be displayed in the issue as text.

Actual results

The link is interpreted and the code becomes:

<script> 
  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ 
  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), 
  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) 
  })(window,document,'script','//www.google-analytics.com/analytics.js&#39;,&#39;ga&#39;); 

  ga('create', 'UA-111111-1', 'auto'); 
  ga('require', 'linkid', 'linkid.js'); 
  ga('require', 'displayfeatures'); 
  ga('send', 'pageview'); 
</script>

Note the URL:

  })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); 

Workaround

Switch the Renderer to the Wiki Style Renderer. For more details, consult our documentation on Configuring Renderers.