When double redirect-fixing bots change redirects as a result of controversial mergers or redirect vandalism, the result often goes unnoticed by the reverting human editor. For example:

Case 1: Controversial merger/redirection

1. Article A is controversially merged/redirected to article B.
2. The bot re-targets redirect C (which initially pointed to A) to article B.
3. The merger/redirection is reverted, and article A is restored.
4. Redirect C is left pointing to B instead of A, where it should.

Case 2: Redirect vandalism

1. Article A is redirected to article B by a vandal.
2. The bot re-targets redirect C (which initially pointed to A) to article B.
3. The vandal is reverted.
4. Redirect C is left pointing to B instead of A, where it should.

If the bots added {{r avoided double redirect|title_of_the_bypassed_redirect}} to the pages they edit, once the changes are reverted, the bad redirects will appear in Category:Avoided double redirects to be updated, helping alert human editors to the issue.

This should probably not be done for double redirects which are results of page moves (those that redirect to redirects tagged with {{r from move}}, which are the large majority of double redirects), in order to reduce unnecessary load. (This was raised by Headbomb here.)