I have reason to believe that hackers at work on the playstation network.
So if someone joins your game and just sits there doing nothing kick them out.
I could be very wrong and it could be nothing but the image below is what happens to my connection when I use my ps4.
btw none of the ip addresses in this image are anything to do with my devices, nothing on my network has an ip address that even comes close to these. My ISP are also looking into it.