I had a few new leads come in without any other information besides an email address, with an action that they filled out a form--but it's the unsubscribe form. I see no other activity for these leads; as in, they were never sent an email to opt out of in the first place. Anyone see something I'm missing?
Could be a few explanations, but in my experience this is usually when one person has some type of alias set up -- meaning they're receiving mail that you are sending to the email address corresponding to their record in your database, but their primary address (and often in this case, the one they think you are sending to) is different.