Steps to reproduce:
Enter Stack Overflow for the first time. You don't have an account.
Ask a question without registering. It asks you for a name and email.
Now suppose you are another user using the same computer, a few days later.
Ask a new question.
By default, the name and email are filled in with the previous ones. But you are allowed to change them.
So edit those fields and enter a new name and a new email.
Post the question.
EXPECTED: the new question should be published with the new user name and email.
OBSERVED: it is published as being asked from the same user as the previous one.
Now, if you are objecting that this is expected behavior (because you want to discourage users from posting with multiple names, because you think that user should register and log in), THEN it should NOT allow you to edit the name and email fields if it is going to ignore any change and take the old values anyway.
What is certainly a bug is that you are allowed to write a new name and email and then everything works as if you had entered the same name and email as before. Don't let me think I'm doing something if I am not allowed to do it.