I know i'm not the reporter of the bug but it looks like the following:
1. open Gwibber
2. reply to a user/post
3 it shows a @name
4.you cant add another user to that same reply with a @ before the name.
What is expected:
being able to reply to all users that you would like and it adds a @ in front of the name
replying to one users and to reply to the same user on the same post leaves off the @ for the second/third/ect...
Is that the right info? if not please add your version or at the very least let us know if that is close/correct