I recently noticed some very bizarre behavior on this old post. The user who asked the question is currently operating under the username "Loop Space". This user seems to have previously operated under a different username; let's call it $OLDNAME so as to not link the old username and the current one. (I believe the user wishes the names not be obviously linked.)

This user also answered the question as a follow-up (answer starts: "I've accepted"). The new username ("Loop Space") appears in the profile view right underneath the question, but $OLDNAME appears in the "author box" below the post itself. The answer is community wiki and has been edited, so it's not really the usual "profile view" that appears beneath the answer.

Whether this bug appears depends on the client, as far as I can tell:

  • it appears in my usual Chrome setup (i.e., on my laptop with my usual extensions);
  • it appears in a private Chrome window on my laptop;
  • it appears in vanilla Firefox (normal and private) on my laptop;
  • it appears in vanilla Edge (normal and private) on my laptop;
  • it appears in Chrome (normal and private) on my Android phone;
  • it does not appear in the StackExchange mobile app on Android.

I think this is because the author box below posts appears differently on mobile than it does on desktop browsers.

I have not noticed this problem on other questions, and I have no idea how I would even go about finding other instances. I have also changed my MO username, and it seems to have correctly propagated to my old posts (including some that were CW). Perhaps it is the combination of CW and being edited by another user?


1 Answer 1


I believe the Meta post Old usernames stick to Community Wiki posts explains what is going on. In particular, this answer by Pops says

Some time in mid or late 2011, a change was made that affected this behavior. Current names are now shown on some old posts, such as the one I used as the example in the question. However, old names are still present in some places, which can be seen in the user card column of these search results (thanks Tim Stone!).

Since the MO post you link to and its answer are from November, 2009, they were before the referenced change was made. This is quite possibly why you see the behavior you noted with this old post, but with it behaving differently now.

  • $\begingroup$ … Why a math mode $2009$? $\endgroup$
    – LSpice
    Commented May 3, 2020 at 14:47
  • 1
    $\begingroup$ @LSpice On the Math SE site, it used to be an unusual text mode font was used which did not render numeric digits very well, so I got into the habit (and I've notice other people doing likewise) to use math mode around all numeric digits. However, I just checked on the math site to find that now (I'm not sure when it changed) but the font is different, so digits actually display quite well. Since that's also the case for here, I've removed the math mode around the 2009 in the answer. $\endgroup$ Commented May 3, 2020 at 20:24
  • $\begingroup$ Thanks for explaining! $\endgroup$
    – LSpice
    Commented May 3, 2020 at 23:39
  • 1
    $\begingroup$ This behaviour occurred on a 2021 answer (also to a CW question). I made an MMO post: Why is the wrong username showing up after a user changes names?. $\endgroup$
    – LSpice
    Commented Feb 25, 2023 at 23:49

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