JIRA.Events.NEW_CONTENT_ADDED event is triggered twice when reloading/refreshing an issue

Summary

When binding JIRA.Events.NEW_CONTENT_ADDED to JIRA issues (eg: via a webpanel), the event will be triggered twice when an issue is refreshed. This is confirmed by adding a console logging to the script:

Steps to Reproduce

1. Create a test plugin, containing a web resource containing a javascript which is attached to the issue view:

   <web-resource key="components-mod-resources" name="components-mod Web Resources">
           <dependency>com.atlassian.auiplugin:ajs</dependency>
           <resource type="download" name="test-script.js" location="/js/test-script.js"/>
           <context>jira.view.issue</context>
   </web-resource>
   

   AJS.$(function() {
       JIRA.bind(JIRA.Events.NEW_CONTENT_ADDED, function(e, context, reason) {
           if (AJS.$('#my-test-element').length != 0) {
               if (reason == JIRA.CONTENT_ADDED_REASON.pageLoad) {
                   console.log("Page Load");
               } else if (reason == JIRA.CONTENT_ADDED_REASON.panelRefreshed) {
                   console.log("Panel Refreshed");
               }
           }
       });
   });
   

2. Once the plugin has been installed on a JIRA instance, access a test issue with the browser console opened.
3. After the issue is loaded, refresh the issue for the first time by clicking on the issue key on the issue view:
   
4. After the issue is refreshed, click on the issue key again and the event will be triggered twice:
   

Expected Results

The JIRA.Events.NEW_CONTENT_ADDED should be triggered once for each time an issue is refreshed.

Actual Results

The JIRA.Events.NEW_CONTENT_ADDED will be triggered twice when an issue is refreshed more than once.

Notes

This behaviour is also reproducible on the Issue Navigator with 'Detail View' enabled, when selecting between issues on the list.

Tested on JIRA 6.3.15.