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?

• … Why a math mode $2009$? – LSpice May 3 at 14:47