Support

No. It's due to a bug in Joomla!. I have seen that in older versions (around 3.3 or early 3.4). Sometimes Joomla! would create a new #__extensions table record for the updated version of a component (ANY component, not just ours!) it was installing, therefore creating a duplicate update record as well. Further to that, for reasons unknown Joomla! would sometimes create a new update site record when updating an extension if the URL was different.

Since we're aware of the duplicate update sites bugs in Joomla! we have code in our post-installation script which looks for duplicate update sites and remove them. However, to keep things safe, we only look for update sites assigned to the #__extensions table ID currently assigned by Joomla! to our extension. If Joomla! had created a duplicate update site under a different extension ID we cannot do anything about it.

Joomla! has similar bugs regarding administrator menu items (the entries under #__components). We are also aware of those and have code that works around them in our post-installation script.

The biggest irony of it all is that our master post-installation script is part of Joomla! since over a year ago as Joomla! includes our FOF framework. The same, of course, goes for our update sites management helper which is used by our installation scripts to refresh the update sites records despite Joomla! bugs.

Unfortunately there is no user interface to remove double entries from Joomla!. When I contributed the Update Sites page of the Extensions Manager they asked me specifically to not include a Delete button. Indeed, that could be just as dangerous as it is useful in cases like yours.

The only way to fix that is through the database. You need to first get a backup of your site just in case :) Then open the #__update_sites table with phpMyAdmin (available through your hosting control panel) and delete the two rows which have a location of "http://cdn.akeebabackup.com/updates/atpro.xml".

Now download Admin Tools from our site and install it without uninstalling the existing version before. The update site should be reinstalled without a duplicate entry.

Confirmed.