How was this posted both 2 hours ago and also on the 15th? I got really confused when someone said something about "monday morning" but all the timestamps read 15th.
https://news.ycombinator.com/pool
There's a "second-chance" pool for posts which didn't get a lot of discussion but the moderators feel deserve more. When it's added to the front page again, the timestamps are updated to make it seem like a fresh post, presumably because people will be more likely to comment.