User's username remains indexed in search after GDPR steps

Description:

After running GDPR scripts and following listed GDPR steps (including flushing index queue), user's username remains indexed from previous mentions tag when doing a full site search. 

This affects all versions of Confluence.

Steps:

1. Mention user on a page and publish it.
2. Disable user
3. Run scripts
4. Clear cache
5. Flush queue 
6. Do a full search for user's username
7. Observe username is visible 

Expected:

No results are returned

Actual:

**Search results are returned that have the user's username visible. 

Clicking on the link shows unknown user