Offline cams still provide snapshots.

I've two stickup cams which claim to be offline - and aren't supposed to be but that's for a different thread. Both of them regularly provide the snapshots they're supposed to provide at 30s intervals. Now one such cam does report unavailable snapshots for a couple minutes, then it regains the ability again for exactly 13 minutes or so, then it will loose it for two minutes, then regain it for 13 and so on and so forth. So every 15 minutes on the timeline for this cam, there are missing snaps. The other cam of this type never drops out at all. And both report offline. They never report online. I should add that live View doesn't function on any of the cams of this type or any other type even when the WiFi connection claims to have been established successfully. That pretty normal? Seems to me if they're offline, I shouldn't be receiving anything from them. Very peculiar if you ask me. Could this be a sign of a hacking?