Hi! We’ve released a new redirects engine about 8 months ago and have tested it pretty thoroughly. In the past days, we’ve migrated all the sites that where still on our legacy redirects engine (gohugo.io is likely one of those). The old redirects engine ignored most broken redirects but the new one is more strict in the interest of better performance and correctness. This is the reason those redirects have only recently caused issues. Let me know if you have any followup questions.
Is the answer I got from Netlify. I think we have fixed them all (I did some grepping), but if not, please shout … Or faster: Just remove the alias in the docs repo and create a PR.