redirect.py needs to log issues it is unable to fix and why on each wiki. There are several flavors of problems that appears on Special:Doubleredirects
1. Self redirects (redirects that point to themselves)
2. Redirect loops (redirects that go in circles)
3. Double redirects formed due to page protection.
4. Inter-wiki redirects (redirects that point to redirects in other wikis)
It would be a lot easier if I had a log of these pages and user can post it on the village pump or perhaps bot can do this monthly for a select number of wikis. The code already provides a warning on the console but when you are running it on 700 wikis like me that becomes a serious chore to follow.