Logged in or not, you're there, Cyber stalking him. And yes, that "last online" thing is, like most features on POF, incredibly unreliable. Especially if he has the mobile app, which basically displays you as online all the time it has internet connection. So if you're on a train going through tunnels it looks like you're going on and offline constantly which many people misinterpret as actively using the site
see the review