When you change your username to have the square brackets around your name "[" and "]", it corrupts a quote. Since BB code uses those brackets having it in your name makes a quote look messed.
Below is are examples of what I am talking about.
Post Example (Click to View)
Image Example (Click to View)
Below is are examples of what I am talking about.
Post Example (Click to View)
Image Example (Click to View)