CONFANCESTORS table obtains duplicate record after a page page re-order to space root

Summary

When moving/re-ordering a page from the page tree and back into the tree again, results in duplicate entries in the CONFANCESTORS table.
It is not known if this causes any functional issues.

Confluence Ancestor table corruption in this Suggestion CONFSERVER-25188 Mentions that Confluence ancestor table status is checked and then we will have automatic rebuild but eventually as a resolution, we have to do a manual rebuild of ancestors table.

Environment

• Confluence 6.5.x 6.6.x and 6.7.0

Steps to Reproduce

1. You need a space with a home page and at least one child page of that home page.
2. reorder the pages such that the child page is on the same level as the home page (so it's an orphaned page)
3. reorder the pages again such that the child page is again a child of the home page
These steps
cause multiple entries in the ancestor table on a freshly installed version of Confluence 6.7 without any plugins installed on the GUI by a non-admin user
Running below query already returns>1:

SELECT A.ANCESTORID, A.DESCENDENTID, COUNT(A.DESCENDENTID)
FROM CONFANCESTORS A, CONTENT B
WHERE B.CONTENTID = A.DESCENDENTID
GROUP BY A.ANCESTORID, A.DESCENDENTID
ORDER BY 3 DESC

The output of the select query is not equal 1 and yet we do not see expected warning inside logs:

Selected ancestors table corruption for pageId: 1234567. 
Access to this page is blocked for all users as inherited permissions cannot be determined. 
To resolve this, rebuild the ancestors table. See https://confluence.atlassian.com/display/DOC/Rebuilding+the+Ancestor+Table

Expected Results

Customer would like to have ancestors table put automatically in sync as this needs them to perform on almost daily basis the same procedure

Actual Results

We need to do the usual manual rebuild procedure of ancestor table
notes

Notes

We have lots of customers who might face frequent problems with ancestors tables and end up with manual workaround and would really appreciate a solution or real automated procedure for cleanup that doesn't need service interruption

Workaround

The steps to resolve this issue is still to rebuild the ancestors' table as described in this KB https://confluence.atlassian.com/x/8qr-Nw