In a very recent question the OP had made considerable amount of progress in proving an inequality. The OP was only left to prove the inequality $x^2y+y^2z+z^2x\le \frac{4}{27}$. Myself knowing that the inequality was quite famous (at least in the contest world). I voted to close it as duplicate of this one which helped the OP finish the proof. (And he/she acknowledges it.)
Thinking over it, I don't know whether what I did was correct. This post with which it has been associated as a duplicate is very different from the original question and it has particularly helped the OP. I really don't know whether I should have closed as a duplicate. Please advice
Should I have answered the question with the link? Or should I have just left it as a comment?
Also in general is it a practice in the site to close questions as a duplicate taking into account the OP's progress? (For example, in this case associating it with a post concerning a sub-inequality the OP was left to prove)