In the admin page to configure smtp, the smtp password has the following description.
"SMTP password. Leave blank if you don't wish to change it."
This is displayed even when the user hasn't entered a password. This could confuse less technical users into thinking that this will modify their password when they enter it.
Better would be to write: "SMTP password. If you have already entered your password before, you can leave this field blank (unless you want to change the stored password)."