This isn't 100% reproducible, but is similar to a programmatic history bug that was fixed a release or two ago that affected Discourse sites a lot. That issue is still fixed but I'm seeing similar behavior again on GitHub. Steps: 1. Navigate to a GitHub repo, say https://github.com/nicklockwood/SwiftFormat 2. Navigate to the latest release from the sidebar on the right. Say, 0.49.17. 3. Try to navigate back. If you'd viewed anything in the tab before going to GitHub it will navigate back to the last page before step 1. If you hadn't viewed anything in the tab before going to GitHub it will work fine. I'll investigate more, but perhaps this is related to time since last view, or perhaps was a glitch with GitHub itself.
*** This bug has been marked as a duplicate of bug 243914 ***