Yes that happens sometimes if the page link broke. A couple of times the link to main puzzle hasn't worked for people from either the Learn tab or site Home, so we re-added it. As its not fair on those who already posted on one, we don't delete it.
Posting the same thing twice.
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It appeared that dailypuzzle has posted the same puzzle twice! Why?
http://www.chess.com/forum/view/daily-puzzles/1192013---royal-breakthrough2
http://www.chess.com/forum/view/daily-puzzles/1192013---royal-breakthrough