This deleted Mathematics question still appears in the search results if you look for its content, e.g. when searching for "it seems they forgot to take the square root in the denominator":

enter image description here

SEDE says it has been deleted on April 4th, so it can't really be a caching issue.

The same problem occurs for this question on Open Source; it can be found when searching for "This question is about a particular part in the process of scientific publishing". SEDE says it has been asked and deleted on June 6th.

Since then, I found a couple of instances on Stack Overflow:

The problem seems to have intensified late 2017 and in January 2018, but then it mostly stopped occurring; only the last two posts are younger.

It seems that undeleting and redeleting the post might solve the issue.

(Originally posted on Mathematics Meta, but I found more instances later.)

  • This is probably also related with the migration of the tag engine to .Net Core. Maybe boolean logic got replaced with true; false and file_not_found?
    – rene
    Jul 19, 2019 at 15:10

1 Answer 1


As you suspected, undeleting and re-deleting the question removed it from the index. With the original deletion so far in the past, it's hard to know why it was missed - so for now, the best we can do is fix up the immediate problem.

If you encounter any other instances of this, please let me know. Thanks!

  • The Open Data question I mentioned is still visible...
    – Glorfindel Mod
    Jul 23, 2019 at 16:07
  • And here's another one for you, on Stack Overflow.
    – Glorfindel Mod
    Aug 15, 2019 at 9:30
  • Deleting/undeleting works there too. I'll betcha there's a race somewhere...
    – Shog9
    Aug 15, 2019 at 21:21
  • and another one: stackoverflow.com/… (I do know you have more pressing matters at hand - I'll remove the other comments and refer to the list in the question.)
    – Glorfindel Mod
    Oct 10, 2019 at 21:07

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