Doesn't seem SMTP related to me; can't change it anyway.
Sparrow is a Mac OS client for Gmail, so there are no SMTP settings, just a name and password.
I assume if the settings were incorrect, I wouldn't be able to send e-mail (which I am) and if this were the problem it would only trigger while sending e-mail. It happens randomly though.
I'm still curious if there's any way to find out if this is some other software sending information on port 993, or if it's just a false-positive and I can turn those specific warnings off.