This question says "asked 23 hours ago" but has answers from April 2014. I'm guessing this is a bug?
It’s not quite a bug, but nor is the reason completely obvious.
There are two questions at play here:
- Why didn't Snape keep or secure his copy of Advanced Potion-Making? (asked yesterday)
- Why did the Half Blood Prince leave his book in the Potions dungeon? (asked 30 Apr 2014)
Originally I closed the new question as a dupe of the older question. But the new one is no longer closed-as-dupe, and has inherited all of the older answers. What gives?
If you look at the old question, you see this notice:
merged by Kevin♦ 3 hours ago
This question was merged with Why didn't Snape keep or secure his copy of Advanced Potion-Making? because it is an exact duplicate of that question.
The merging process mean that all the answers on the old question move to the new question, but their original timestamps are preserved. That’s why the new questions has answers which were written before it existed – because they were!
I only realised this because I did the original dupe-closing. How could you tell if you didn’t know about the other question? It’s not easy to find on the new question, but if you look in the edit history of one of the answers (for example), you’ll see this line:
Post Merged (destination) from scifi.stackexchange.com/questions/55309/…
occurred 3 hours ago
which tells you when the merge occurred, and where the answer was originally posted.