This seems to be part of the way Buddypress works, you can’t change your login name and this is the name it uses for messaging, hence the @name issue you mention. it means that users can get pretty confused if people change their display name.
I’m not aware of anyway to change this.
The @-name you see is slightly different to the “full name” displayed in user profiles. The @-name can be thought of as a username; a unique identifier for that member. The full name is just a line of text that can be anything the user likes. Two users can have the same full name, but no two users can have the same username.
I understand about usernames, that they are unique, can’t be changed and are the names used when logging in. They are basically the account id name. I’m referring to the nickname. For example, when I set up a dummy account, I used the username Wxyz and the nickname wxyz1. In this case, Wxyz1 appeared as the page title (over the photo) and @wxyz1 appeared next to the photo (in my theme). In the profile, I edited the nickname from @wxyz1 to Shirley. Now, the name Shirley appears as the page title of the profile over the photo, but @wxyz1 still appears next to the photo. I don’t know where the @wxyz1 is coming from, because it no longer shows up in the dashboard as username, first name, nickname or display name. Does you know how to change this?
I mean “Do you know how to change this”, not “does you” 🙂
Which theme are you using?