"Edit" or "Add" link redirects to the front page (Chrome)

1. Open the Chrome Developer Tools by right-clicking the page and selecting "Inspect".
2. Select the "Network" tab.
3. Check "Disable cache"
4. Retry the action that previously failed. It should now work.
5. Close Chrome Developer Tools and go on with your life.

Transitioning the site to HTTPS-only appears to solve this issue.