Development Assistance Chat format element repeating

Hello,

I am trying to display a String before the format but I don't want to modify the formats applied by other plugins. What I am doing is event.setFormat(extra_element + event.getFormat());.

This is my listener:

PHP:

public class PlayerChatListener implements Listener {
  
    @EventHandler
    public void onPlayerChat(AsyncPlayerChatEvent event) {
      
        Player player = event.getPlayer();
      
        event.setFormat(ChatColor.GREEN + Players.getRepString(player) + event.getFormat());  
    }
}

What happens is that when I talk in chat, it displays the string, but it displays it twice right against itself. I have tried many different ways to get a different result, but no matter what I do it inserts the number twice instead of once.

Thank you for any help.