I have the same problem, it will happens 2-3 times a day when I tried unlock the phone, I even replaced the phone but it still have the same problem, the apps I installed is all the basic apps that everybody use on a daily basis like face book, whatsup etc. nothing special, and I seldom install apps, it's like only around 10 apps I've downloaded on the phone. Since I'm not the only one , I think it's not about the apps, it's phone itself got issues, it's just I'm not sure what could be the problem as we are all not technicians. A bit disappointed about note 5, I've been use note phones for quite long time and never encounter this kind of problem before. Just wish Samsung can notice about this and provide updates for us to solve the problems. BUT, strange thing is two of my friends also use note 5 but it seems they don't have this problem at all, weird, so I give up to communicate with Samsung anymore with regards to this issue. first time I bought the black version, then replace with gold version (I gave credit to Samsung about their service as they indeed replaced the phone for me), but problem the same, anyway, whatever it is, phone problem or app problem, lucky it won't cause a very big problem so I can still somehow use it as per normal.