I saw Would normal people accept a path of immortality given the following, specific restrictions? bumped to the top of the front page as "answered" despite being "on hold", so got curious.
I got even more curious when I saw that the question was put on hold 2016-08-15 20:53:24Z but jorfus posted an answer (ID 51783) 2016-08-15 21:15:11Z, a full 22 minutes after the question was supposedly put on hold.
How could that happen?
There is a grace period for answers that are in flight when a question is closed, because it's really discouraging and frustrating to spend an hour writing a good, solid answer to a question only to have it yanked away from you five minutes before you click "post". (That's a general statement; I haven't looked at this particular question.) So, if an answer is already being written, it can be posted for up to a couple hours after the question gets closed. You can't start a new answer post-close, though, and if you had one in progress and navigated away from the page for some reason, I don't know if you could go back in your browser and still post.
I think this Meta.SE post is not completely accurate any more, but it's the closest thing I could find to a canonical explanation. (That post says four hours; I don't know if that's really true.)
