Moved to correct forum. As to your question, I can't reproduce this... I created a new DNAS2 stream with autoDJ type set to "None", went to the "Server Overrides" tab and set "Public server: Automatic" and hit "Create".
Going back and editing the account, on the "Server Overrides" tab it's still set to "Automatic" and the configuration file contains "publicserver=default".
Instructions to reproduce...?