"Anonymous Logons" are normal. It doesn't necessarily mean that there's a security issue. The fact that there's no network information shows that it's just local system activity. Windows talking to itself.
To substantiate, Anonymous logon occurs in cases where users/computers when try to change the passwords before being authenticated first. It primarily happens for all computer accounts. More over, 'everyone' group has 'Change Password' permission for all objects which facilitate the users/computers to change their passwords when they expire before without having to be authenticated first.
You may also make use of the following article that validates the above statement.