You are absolutely correct - if you e-filed you should not mail your tax return in!
Even if you e-file, there are some states that require that you print out one of their forms and sign it when you e-file. That Form GA-8453 will be part of your printed state tax return. So if you print out your state return, that form will be part of the package. Once you print it, all you have to do is sign it and hang on to it. You do not need to mail it to the state.
