The title is probably a little hard to grasp, so let me explain what I mean with an example. I'll make it a very specific example, which will ignore other closing criteria for the sake of simplicity.
- A question (Q1) gets asked: Why is potassium permanganate solution purple?
- This question goes unanswered for days, maybe weeks or even longer. Long enough to be off the radar for most of our users.
- Another question (Q2) gets asked: How is the permanganate ion responsible for the color of the solution?
This is essentially the same question as Q1, which may or may have not been linked to it via comment. By the ordinary user it cannot be closed as a duplicate.1
- Suppose Q2 now attracts an answer2 (or more), because it wasn't possible to close the question (or maybe not even desired, see 1).
What should now happen to the two questions?
I see essentially two scenarios. The questions are still duplicates.
We usually close questions as duplicates of other questions because they have been answered already. And most of the times the newer question will get closed in favour of the older one.
Option: We can still close Q2 as duplicate of Q1 and carry on normally.
We apply similar logic and link the unanswered duplicate to the answered one, which would be in the spirit of the redirect.
Option: We close Q1 as duplicate of Q2.
There are probably other scenarios which I did not consider. If you can think of something more clever or simply want to add to the discussion I am looking forward to your answer.3
Notes: 1 Moderators can do it, so you can custom flag the question. Whether it is beneficial to close the question in the first place is another thing to discuss, but essentially it is possible. I only use this option if the same question gets asked in rapid succession by the same user. 2 Answer in the sense that the algorithm considers the question as answered, i.e. a score of 1 and above, or accepted. 3 An answer is much preferred over a comment.