An anchor link's name changes after editing the page with Collaborative Editing switched on or set to limited

Summary

When a link to an anchor is created, the subsequent attempt to edit a page causes the link to change its name to <page title>#<anchor link name>.

Note: This can only be replicated while Collaborative Editing is set to 'On' or 'Limited' and can be hardly replicated in new pages.

Steps to replicate

1. Import this space backup (space key: TEST): Confluence-space-export-160823-2.xml.zip
2. View the page 'the lion king'. You'll see at the bottom of the page that there's anchor link named 'top' that brings you to the top of the page once you click on it.
3. Edit the page 'the lion king'.
4. Scroll to the bottom of the page editor.

Expected results

The anchor link should not change from the original link name 'top'.

Actual results

The anchor link has changed from 'top' to 'the lion king#top'.
An error message stating that you are viewing a previous version of the page also appears at the top of the page when the anchor is clicked.

This behavior also exists when a page containing a link to an anchor is copied using (...) > Copy. For these pages, this behavior exists regardless of whether the original page was corrected or not. When the broken link on the copied page is clicked, the error message mentioned above does not display.