Purpose

Confluence relies on your browser's local storage to remember the people you mention regularly. To mention someone using autocomplete, type '@' in the editor then start typing their name. You may see different results if you switch devices, or don't allow local storage. Confluence doesn't indicate whether someone is a creator, contributor or commenter when they are also a recent mention (because we're grabbing them straight from your local storage, not the page itself).

Should you wish to reset this list to reflect more current information, you simply need to clear the Local Storage in your browser for your Confluence site. Once cleared, the list with automatically repopulate based on the people you mention regularly.

Solution

Safari

1. Select Safari > Preferences… from the menu in Safari.
2. Go to the Privacy tab.
3. Click Manage Website Data
4. Search for the Confluence site in question
5. Highlight the site and click remove

Example:

Chrome

1. Click the button at the left of the address bar, either:  or 
2. Select Cookies
3. Expand your Confluence site
4. Highlight Local Storage, or highlight the entire site to remove everything
5. Click Remove
6. Click Done

Example: