Random period in front of a user in the Users area of WP

I upgraded to the most recent version of WP 5.2.2. When I go to the Users section I see my normal users, but on one of those users, there is a random period (.) in front of the username in the list. If I edit the user, the period is not there. Is this just a bug or is there some purpose for it? In this case, this user hasn’t signed in to the site in a long time. There is no other user that has this period in front of their name.

To be clear, the username looks like this: .johndoe .

Other users in the list are fine.

Thanks for any help.