This has been reported a long time ago; things might very well have been fixed by now. I can hardly imagine this is a real issue, but *maybe* it's not too nice for SEO or the data dump? So:

[A question][1] on Super User had its comments about duplicates removed by a moderator. However, the "Linked" section still showed the links *for many months*, until somebody edited an answer:

<a href="https://i.sstatic.net/jh00Y.png"><img src="https://i.sstatic.net/jh00Y.png" width="300" alt="Linked section still shows the deleted references"></a>

[Jeff writes][5] that links are cleaned up every 30 days, or whenever a post is edited. The first was not true for this example: the links were definitely still there almost 4 months later (on May 4th 2011). Looking again in October showed the links were okay, but at that time the post had been edited.

I think [one link][2] was still used in the 4 close votes that had not expired yet. [The other][3] was a link to another duplicate, which might only have been in the comments, not in any vote. (As I voted, I only see "You have already voted to close this question" so cannot validate which duplicates were used. Both links were in my comments.)

This is related to [Posts linked in deleted answers still show up under “Linked”][4], which meanwhile has been tagged `status-bydesign`. But while 10k can see deleted answers, deleted *comments* cannot been seen by anyone but moderatos.



  [1]: https://superuser.com/questions/232813/what-goes-on-when-requesting-a-url-in-a-browser
  [2]: https://superuser.com/questions/182800/explain-how-the-internet-works-to-a-complete-computer-novice
  [3]: https://superuser.com/questions/157408/what-happens-when-you-enter-a-url-in-your-browser
  [4]: http://meta.stackexchange.com/questions/64743/posts-linked-in-deleted-answers-still-show-up-under-linked
  [5]: http://meta.stackexchange.com/questions/47898/broken-link-in-linked-posts-section/79318#79318