While viewing related questions on Meta Super User, I noticed two questions with the same title.

Initially I assumed this was a strange coincidence or a bug in the system. But then I realized the two questions were literally exact duplicates.

Same title, author, comments, answers, migration path, top answer, and related posts.

Even the vote counts for comments and answers are similar between both questions.

Strangely, none of the comments on the duplicate question are linked to any specific users. Each of the profile names is unclickable, as if the comments were somehow all made by anonymous or deleted users.

How is it possible for there to be two exact duplicate questions, including duplicate comments and answers?