I have several WordPress webpages. On most of them I noticed a strange change. I have Users with different roles, most of them are authors. For reasons I don’t know (I didn’t change anything) the username (!) of all the users was changed to the admins username (!). Everything else remained the same. I also noticed that when I go on “Edit profile” on one of these profiles although I didn’t change anything, when I try to go to another page it shows the “your changes to the profile won’t be saved” dialogue.
I then tried to create a new user, giving this user a distinct username. But even then, after the user was created, the username was also changed to the admin’s user name.
Login of a user using the nickname, works, but it takes a long time.
Did anybody else have these problems? What is this?